An Introduction to Entomology

or
Elements of the Natural History of Insects
Volume 3
with plates
By William Kirby, M.A. F.R. and L.S.
Rector of Barham
and
William Spence, Esq. F.L.S.

Second Edition
Vol. III

London
Printed for
Longman, Hurst, Rees, Ormi, and Brown,
Paternoster Row.

1826

There is a facsimile available at gallica.bnf.fr

Page 38

From this table you see that several insects included in it exceed some of the smallest Vertebrata in bulk. In the Mammalia, the Sorex Araneus, called by the common people here the Ranny, is not more than two inches long excluding the tail; and the Mus messorius, or harvest-mouse, peculiar to the southern counties of England, is still more diminutive: so that to these littie animals, the larger Dynastidæ, Goliathi, and Prioni, &c., appear giants, and may compete with the mole in size. Even some of the beetles of our own country, as the great Hydrophilus, the stag-beetle, &c, are more bulky than the two first-named quadrupeds. Amongst the birds, many Picæ, Passeres, &c., yield to several insects in dimensions, and their wings when expanded do not extend so far as those of not a few Lepidoptera. The great owl-moth of Brazil (Erebus Strix) in this respect is a larger fowl than the quail. Those beautiful little creatures, the hummingbirds (Trochilus L.), the peculiar ornament and life of tropical gardens, which emulate the most splendid butterflies in the brilliancy of their plumage, are smaller than a considerable number of insects in almost every order, and even than some of those that are natives of Britain. Various reptiles also are much inferior in size to many of the inseets of the above table. The smallest lizard of this country would be outweighed by the great British beetles lately mentioned, and the mole-cricket (Gryllotalpa vulgaris); and some of the serpent tribe are smaller than the larger Scolopendræ and Iuli. Amongst the fishes also, though some are so enormous in bulk, others in this respect yield the palm ro several insects. The minnow and the stickleback that frequent our own pools and streams are considerably inferior in size to some of our water beetles.

Page 39

In looking over the table, and comparing the different species that compose it with each other, you will perceive that the largest insects of the two sections of Hermptera, of the Lepidoptera as to their body merely, of the Hymenoptera and Diptera, in general size fall considerably short of those of the other orders; and that certain individuals of the Orthoptera and Aptera bear away the palm in this respect from all the rest. In the Coleoptera the giants, with the exception of the Goliathi, are chiefly to be found amongst the timber devourers in the Lamellicorn and Capricorn tribes. Of orthopterous insects the Phasmidæ present the most striking examples of magnitude; and in the Neuroptera, the Agrionidæ of great length.

It is worthy of remark here, that although the tropical species of a genus usually exceed those of colder climates in size, the Gryllotalpa of Brazil is very considerably smaller than that of Europe: whether this is the case with the rest of the cricket tribe I have not had an opportunity of ascertaining. The Lepidoptera, though often remarkable for the vast expansion of their “sail-broad vans,” if you consider only their bodies, never attain to gigantic bulk. Even the hawk-moths (Sphinx L.), though usually very robust, make no approach to the size of the great beetles, or the length of some of the spectres (Phasma) and dragon-flies (Agrionidæ). With regard to the superficial contents of their wings, a considerable difference obtains in different species where they expaud to the same length - for the secondary wings are some times smaller than the primary, and sometimes they equal them in size. In some instances, also, the latter although long are narrow, and in others they are nearly as wide as long: regard, ttherefore, should be had to their

Page 40

expansion both ways. In the Hymenoptera and the principal giants are to be found in the predaceous or blood-sucking tribes, as Scolia, the Sphecidæ, Pompilidæ, Vespidæ, belonging to the former order; and the Asilidæ and Tabanidæ to the latter. The true and false humble bees (Bombus and Xylocopa) and the fly tribe (Muscidw), though they sometimes attain to considerable size, scarcely afford an exception to this observation. Amongst the Aptera none of the Hexapods strike us by their magnitude, and few of the Octopods, though the legs of some of

a

S. minutissima of Marsham is synonymous with Dermestes atemarius De Geer, Scophidium atomarium Gyllenh., and Latridius fascicularis Herbst., but surely arranging with none of these genera, being sufficiently distinguished from them and every other insect by its singular capillary wings. In my cabinet it stands under the name of Tricnopteryx K.

the Phalangidæ inclose a vast area. That in the table would with them describe a circle of six inches diameter, though its body is little more than a quarter of an inch in length. The Myriapods exceed most insects in the vast elongation of their body, which with their motion gives them no slight resemblance to the serpents. In the class Arachnida, the bird-spiders (Mygale) are amongst the principal giants, nor do the Scorpions fall far short of them - both of them when alive often alarming the beholder as much by their size as by their aspect.

But as I have before observed, generally speaking, one of the most remarkable characters of the insect world, is the little space they occupy; for though they touch the vertebrate animals and even quadrupeds by their giants, yet more commonly in this feature they go the contrary way, and by their smallest species reach the confines of those microscopic tribes that are at the bottom pf the scale of animal life. I possess an undescribed beetle, allied to Silpha minutissima E.B.^a, which, though

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furnished with elytra, wings, antennæ, legs, and every other organ usually found in the order it belongs to, is absolutely not bigger than the full stop that closes this period. In several other coleopterous genera there are also very minute species, as in Cryptophagus, Anisotoma, Agathidium, &c. I know no orthopterous insect that can be called extremely minute, except that remarkable one found on the Continent in the nests of ants, the Blatta Acervorum of Panzer^a,

a	Panz. Fn. Germ. Init. lxii, 24. Comp. Hor. Entomolog. Addenda, &c. 523.

but now called, I believe, Myrmecophilus: nor indeed any in the Hemiptera, Neuroptera, and Diptera, that approach the extreme limits of visibility: but in the Lepidoptera, the pygmy Tinea occultella is almost invisible except in flight, being scarcely thicker than a horse's hair, and proportionably short; indeed, many others of those lovely Lilliputians, the subcutaneous Tineæ, decorated with bands of gold and silver, and studded with gems and pearls, that in larger species would dazzle the beholder's eye, are in size not much more conspicuous. In the Hymenoptera order, Ichneuman Punctum of Dr. Shaw, which forrns so striking a contrast to his giant Phasma dilatatum, being placed together in the same plate; and another that I possess, under the trivial name of Atomos, would elude the searching eye of the entomologist unless when moving upon glass. Linné named the tribe of parasites which these belong, Minuti, on account of their generally diminutive size. But these little minims, under the superintendence of Providence, are amongst the greatest benefactors of the

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human race, since they keep within due bounds the various destroyers of our produce. The number of minute species of insects seems greatly to exceed that of large ones, at least in Europe, of which it may be asserted probably with truth, that two-thirds are under a quarter of an inch in length, and one-third not exceeding much a duodecinml of it. It might hold good perhaps in Coleoptera, Hymenoptera, Diptera, and Aptera: but in Orthoptera, Hemiptera, Neuroptera, and especially Lepidoptera, a large proportion would be found to exceed three lines in length. Neither can it be affirmed of extra-European species, of those at least preserved in cabinets, amongst which it is rare to find an insect less than the fourth of an inch long. This, however, must probably be attributed to the inattention of collectors, who neglect the more minute species.

Though size forms a pretty accurate distinction between insects and the great bulk of vertebrate animals, it affords less assistance in separating them from the invertebrate classes, which are of every size, from the monstrous bulk of some Cephalopoda (cuttie-fish) and Mollusca (shellfish, &c.) to the invisible infusory animalcule: but external characters, abundantly sufficient for this purpose, may be drawn from the general covering, substance, form, parts, aud organs of the body. As I shall enter into pretty full details upon this subjeet when I come to treat of the external anatomy of insects, I shall here, therefore, only give such a slight and general sketch of the distinctions just mentioned, as will answer the end I have in view. I must here repeat what I have before observed, and what it is necessary that you should alays bear in mind, namely,

Page 659

twelve in the hexapods that have fallen under my notice, by SIX dots.

1. In this arrangement the legs are all planted near to each other, there being little or no interval between the pairs, and between the legs cf each pair. It is exemplified in the Lepidoptera, Blatta, and many Diptera.

a	It is by this arrangement of the legs that Pachysoma is principally distinguished, as a subgenus, from Scarabæus McL.

2. Similar to the preceding, but the anterior pair are distant from the two posterior; exemplified in the bees (Apis) and most Hymenoptera, Chironomus: Scutellera; Pachysoma K.^a

3. Like the last, but the posterior pair is distant from the two anterior. Examples: Silpha, Necrophorus, Telephorus, &c.

4. Similar to the last, but the legs of the posterior pair are more distant from each other than the four anterior. Ex. Curculio L.

5. The legs of each pair near each other, but the pairs distant. Ex. Gibbium.

6. Both the legs ofeach pair and the pairs distant. Ex. Blaps, &c.

7. Anterior pair distant from the two posterior, and the legs of the middle pair rather more distant from each other than those of the other pairs. Ex. Scarabæus McL.

8. Like the preceding, only the legs of the middle pair are at a much greater distance from each other. Ex. Copris McL.

9. Legs of the two posterior pairs distant. Ex. Hister, Scaphidium.

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10. Like the preceding, but the posterior legs more distant than those of the middle pair. Ex. Lygæus.

11. Like the last, but the legs of the anterior pair also distant. Ex. Velia.

12. The arms distant, intermediate legs more distant, posterior legs close together. Ex. Byrrhus L.

a	See above, p. 37.
b	Monogr. Ap. Angl. i. t. xi. Apis**. d. 2. a. f. 18. ii. 296-.
c	Oliv. Ins. 68. t. i f. 8.
d	Ibid. n. 6. t. iv. f. 22.

5. Proportions. In general the legs of some insects are disproportionally long and slender, as in Phalangium Opilio and some species of Gonyleptes^a: those of others are disproportionally short, as in Elater, &c. With regard to their relative proportions, the most general rule is, in Hexapods, that the anterior pair shall be the shortest and most slender, and the posterior the longest and thickest; but there are many exceptions: thus, in Macropus longimanus, Clytra longimana, &c., in the male the arms are the longest; again, a thing that very rarely occurs, in the same sex of Podalirius retusa the intermediate legs are the longest^b; but in Rhina barbirostris and many weevils they are the shortest: in Saperda hirtipes Oliv.^c the hind-legs are disproportionally long: with regard to thickness, they are in general extremely slender in Cicindela, and in the Scarabæidæ very thick. In Goliathus Cacicus the arms are more robust than the four legs^d; in Gyrinus the latter are more dilated than the former; in many Rutelidæ, and particularly in the celebrated Kanguroo beetle (Scarabæus Macropus Franc.) the hind-legs are much the thickest; in a new genus of weevils from Brazil (Plectropus K.), the intermediate pair are more slender than either the arms or the posterior pair

Page 661

6. Clothing. The hairs on the legs of insects, though at first sight they may seem unimportant, in many cases are of great use to them, both in their ordinary avocations and motions: but as most of these were sufficiently noticed when I treated of the sexes of insects^a,

a	See above, p. 305-.
b	This variety appears to differ very little from the Curculio imperialis of Fabricius and Olivier, except in the remarkable hairiness of its legs.
c	VOL. II. p. 563.
d	Oliv. Ins. n. 67. t. xx. f. 156.

I shall not here repeat my observations, but confine myself to cases not then adverted to. Some insects have all their legs very hairy, as many spiders, the diamond beetle (Entimus imperialis), or at least a species very near it and common in Brazil^b, &c.: in others they are nearly naked, as in the stag-beetle. In the Crepuscular Lepidoptera (Sphinx L.) and some of the Nocturnal ones (Bombyx L.) the thighs are much more hairy than the rest of the legs: and in Lucanus, Geotrupes, and many other Lamellicorns, &c., the anterior ones have a yellow or golden spot at their base, composed of decumbent hairs, which prevent them from suffering by the violent friction to which they are exposed in burrowing. In most Petalocerous beetles the tibiæ are set with scattered bristles, and sometimes the thighs. The Tiger beetles (Cicindela) are similarly circumstanced: but the bristles, which are white, are generally arranged in rows. In Dytiscus, Hydrophilus, &c., the four posterior tarsi; and in Notonecta the posterior pair, and also the tibiæ - are fringed on each side with a dense series of hairs, whieh structure assists them in swimming^c. The tarsi, especially the anterior pair, in a certain family of Lamia F. (L. papulosa, &c.^d), are similarly fringed, only tbe hairs curl inwards; and the hand

Page 662

in Sphex and Ammophlia, but not in Pelopæus and Chlorion, is fringed externally with long bristles.

7. Composition. With regard to their composition, both arms and legs generally consist of five pieces, which Entomologists have denominated - the coxa or hip - the trochanter - the femur or thigh - the tibia or shank - and the tarsus or foot. Where the structure and use of the fore-leg is different from that of the four hind-legs, I propose calling these pieces by names corresponding with those which anatomists have appropriated to the arm in the higher vertebrate animals: thus, as you will see in the table, I call the whole fore-leg the brachium or arm; and the coxa becomes the clavicula or collar-bone; the trochanter, the scapula or shoulder-blade; the femur, the

a	See above p. 591. Some physiologists have been of opinion, that in birds, what is called the thigh should properly be denominated the tibia, and that this last is really the tarsus. Illiger, Terminologie, 184. § 185. n. 1246.

humerus or shoulder; the tibia, the cubitus or arm; the tarsus, the manus or hand. But let me not lead you to suppose that the pieces, either in the arms or legs of insects, which are there named after certain others in vertebrate animals, precisely correspond with them - by no means - since that is a very doubtful point; and some of them, as the trochanter, clearly do not. Many gentlemen skilled in anatomy, as I have before observed^a, have thought that what is regarded as the coxa in insects really represents the femur: but there are considerable difficulties in the way of this supposition, several of which I then stated. I shall not however enter further into the subject, and take the above names; since this application of them is so general and so well understood, except with

Page 663

regard to the fore-leg, under certain circumstances, as I find them. I shall now consider them in the order in which I have named them.

a. Coxa or Clavicula^a. The coxa is the joint that conneets the leg with the trunk of the insect. With regard to their shape, the most general form of the four anterior is more or less that of a truncated cone: in the Staphylinidæ, however, they tend to a pyramidal or four sided figure; as do the whole six in the Trichoptera: in numbers of the weevils and capricorns they are subglobose; in the Lamellicorns they are mostly oblong, and not prominent: the posterior pair in the Coleoptera are generally flat and placed in a transverse position, and more or less oblong and quadrangular: in Elater, &c., they are cuneiform: in Haliplus Latr. they are dilated, and cover the

a	PLATES XIV. XV. XX VII. p.
b	PLATE XV. FIG. 1. p", r".
c	PLATE XXVII. FIG. 27.

thigh^b: Buprestis, Copris, &c., they have a cavity that partly receives it: the corresponding part, the clavicle, in the arm of Gryllotalpa, is very large and remarkable; viewed underneath it is triangular, and trifid where the trochanter articulates with it: in that of Megachile Willughbiella the clavicle is armed with a spine^c. As to their proportions, the most general law seems to be, that the anterior pair shall be the shortest and smallest, and the posterior the longest and largest. In some instances, as in Buprestis, the two anterior pair are nearly equal; in others (Mantis, Eurhinus K.), the anterior are the longest, in the former as long as the thigh, and the four posterior the shortest: in the Trichoptera, Lepidoptera, &c., all are nearly equal; in Mantis the two posterior, and in Phengodes the intermediate pair are the largest; but

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in Necrophorus they are the smallest :- though almost universally without articulations, in Galeodes the clavicle consists of two and the coxa of three^a.

b. Trochanter or Scapula^b. This is the second joint of the leg: and if the coxa is regarded as the analogue of the thigh in vertebrate animals, this should seem to represent the patella or rotula, vulgarly called the kneepan. Latreille and Dr. Virey consider this articulation as merely a joint of the coxa^c; but if closely examined, especially in Coleopterous insects, you will find it so fixed to the thigh as scarcely to have separate motion from it, and in many cases it seems to be merely its fulcrum; but I am not aware that any instance occurs in which it has not motion separate from that

a	L. Dufour, Descr. des six Arachn. &c.: Annales Generales, &c. 1820. 19. t. lxix. f. 7. d.
b	PLATE XIV, XV, XXVII. q".
c	N. Dict. d'Hist. Nat. xvi. 195. xxvi. 157.

of the former joint.

As to its articulation with the coxa, - in the Coleoptera it appears to be of a mixed kind; for it inosculates in that joint, is suspended by ligament to its orifice, and its protuberances are received by corresponding cavities in it; and its cavities receive protuberances, which belongs to a ginglymous articulation. I have observed two variations in this Order, in one of which the motion of the thigh and trochanter is only in two directions, and in the other it is nearly versatile or rotatory. The Lamellicorns afford an example of the first, and the Rhyncophorous beetles or weevils of the second. If you extract from the coxa the thigh with the trochanter of the larger species of Dynastes McL., you will find that the head of the latter is divided into two obtuse incurving

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lobes or condyles; that on the inner side heing the smallest and shortest, and constricted just below its apex; and that under this is a shallow or glenoid cavity, terminating posteriorly in a lubricous flat curvilinear ridge. If you next examine the trochanter in articulation with the coxa, you will perceive that the head of the former inosculates in it, that the lower condyle is received by a sinus of the coxa, which also has a lubricous very shallow cavity corresponding with the ridge, in which it turns; and in the head of the coxa, on the lower side, is an external condyle, which is received by a sinus comnmon to both, of the head of the thigh and of the exterior side of the trochanter^a,

a	PLATE XXVII. FIG. 12. b.

in which it likewise turns: this last condyle has also an internal protuberance, which appears to ginglymate with a cavity of the trochanter: from this structure the leg is limited chiefly to amotion up and down upon two pivots, or to fold and extend itself. You will find an articulation very near this, but on a smaller scale, in the stag-beetle. In the other kind of articulation, which admits of freer motion, the head of the trochanter is prolonged, and the process terminates in a short interior condyle, which appears to work in a corresponding cavity of the interior of the coxa; and the base of the process is encompassed by a ridge with a cavity behind it, which is received by another of the lower part of that piece, and admits a corresponding ridge - a structure that allows a rotatory motion, In the hind-legs of this tribe the motion is chiefly limited to folding and extending; in Carabus, &c., also the head of the trochanter is nearly hemispherical, and the articulation

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approaches ball and socket. In most of the other Orders, the Hymenoptera excepted, there is little or no inosculation, the trochanter being simply suspended by ligament to the coxa as well as to the thigh, its connection with the latter is similar in Coleoptera but in Cicindela, &c., it inosculates in it. The part we are considering varies in its position with respect to the thigh: in the hind-legs of Carabus, &c., it forms a biteral fulcrum on the inner side of that part, and does not intervene between its base and the coxa; the muscles from the latter entering the former, not at the bottom of the base, but at its side: but in the four anterior legs it forms their base, as it does in all the legs in Apion,

a	PLATE XXVII. FIG. 20. q".
b	Ibid. FIG 28.

and in all the Orders except the Coleoptera, cutting them entirely off from contact with the coxa: in the Lamellicorns they cut off part of the base obliquely, but so as to permit their coming in contact with the condyle of the coxa, as before mentioned. In the Ichneumonidæ and some other Hymenoptera the trochanter appears to consist of two joints particularly visible in the posterior legs^a.

As to size in general - the part in question is smaller than the coxa; but in Notonecta it is larger, and in the dog-tick (Ixodes Ricinus) longer than that joint. It exhibits few variations in its shape or appendages worthy of particular notice. In general, in the Coleoptera it is triangular or trigonal; but in Carabus L., in the hindleg it is oblong or rather kidney-shaped; in that of Necrophorus^b it terminates in one or two teeth or spines, varying in length in the different species: in the other Orders it is not remarkable in this respect.

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c. Femur or Humerus^a. The femur or thigh is the third, and usually the largest and most conspiceous joint of the leg. In the hypothesis before alluded to^b it is considered as the analogue of the tibia of vertebrate animals. With regard to the articulation of this part with the trochanter, it has been sufficiently explained under that head, and that with the tibia I shall treat of when I come to that joint. As to the size of the thighs, and their relative proportions to each other and to the remaining joints of the leg, the most general law is, that the anterior pair shall be the shortest and smallest, amd the posterior the longest and largest. With respect to the remaining articulations, most commonly the thigh is longer and larger than the tibia,

a	PLATE XIV. XV. XXVII. r"
b	See above, p. 591, 662.
c	VOL. II. p. 314-.
d	Linn. Trans. xii. t. xxi f. 12.

and the tibia than the tarsus. But there are numerous exceptions to both these rules. With respect to the first, we may begin by observing that the increase of the magnitude of the thigh, from the antetior to the posterior pair, is usually gradual: but in many jumping insects, and likewise many that do not jump, the posterior pair are suddenly and disproportionally thicker than the rest^c. Again, in many insects the anterior pair are the longest and thickest, as in Macropus longimanus, Bibio, Nabis, &c.: in others, the intermediate exceed the rest in magnitude, as in Onitis Aygulus, cupreus; Sicus flavipes, &c.; in many Lamellicorns all the thighs are incrassated and nearly equal in size: but in some, as Ryssonotus nebulosus McL.^d, the intermediate pair are rather smaller than the rest. With respect to the second rule - in some, as in the male of Macropus lorngimanus, the anterior tibia, though more

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slender, is longer than the thigh; in Hololepta maxillosa it is longer and more dilated; in Lamia marmorata, or one related to it from Brazil, the intermediate pair are longer; in Ateuchus gibbus and others of that tribe the posterior thighs are smaller than the tibiæ: and, to mention no more; in Gallichroma latipes the posterior tibia is wider than the part last named. Again, the tarsi are as long as either tibia or thigh in many of the larger Dynastidæ, as Megasoma Actæon, &c.; longer than either in Melolontha subspinosa F.; and in Tiphia, Scolia and affinities, often as long, or longer than both together.

a	Stoll Spectres, t. xvi. f. 58, 59.
b	Ibid. t. xviii. f. 65.

As to shape, - the thigh, especially in the fore-leg, varies considerably: most generally it is flat, linear, and a little thicker where it is united to the tibia, on the outer side convex, and concave next the body; but in many it is gradually thicker from the base to the apex: in some Cerambyces (C. thoracicus) it is clavate; in others of this genus and Molorchus they may be called capitate; in Pterostichus they are rather lanceolate; in Onitis Sphinx the humerus is triangular, and the intermediate thigh rhomboidal; in Bruchus Bactris it is bent like a bow; and in some Brazilian Halticæ it is nearly semicircular. The humerus in Phasma is attenuated at the base; in Empusa gongyloides it is at first ovato-lanceolate, and terminates below in a kind of footstalk^a; in Phasma flabelliforme it is dolabriform^b; in Mantis often semioval or semielliptical, and thickest ut the inner edge, which affords space for two rows of spines with which it is planted. In Phyllium siccifolium all the thighs are furnished, on both sides with a foliaceous appendage nearly

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from base to apex^a: in a species of Empusa (E. macroplera), the four posterior ones are so distinguished only on their posterior side^b: others of this last genus, as E. gongyioides, have an alary appendage on both sides at the apex of these thighs^c; and another family, as E. pauperata, have only one on the posterior side^d. The thighs of no insect are more remarkable for their elegant shape, - tapering gradually from the base to the apex, where they swell again into a kind of knee, -

a	Stoll Spectres, t. vii. f. 25.
b	Ibid. t. viii. f. 30.
c	Ibid. ubi supr.
d	Ibid. t. x. f. 40.
e	PLATE XIV. FIG. 5. This appearance of scales on the thighs is principally confined to this tribe.
f	PLATE XXVII. FIG. 23.

than the posterior ones of the locusts (Locusta Leach); each side of these thighs is strengthened with three longitudinal nearly parallel ridges, and the upper and under skies are adorn ed by a double series, some coalescing as they approach the tibia, of obique quadrangular elevations resembling scales^e.

I shall next say a few words upon the spines and other processes which arm the thigh. Those moveable ones of Mantis which help to form a fearful instrument of destruction, have just been mentioned, and similar ones, but less conspicuous, arm the intermediate thighs of Sicus flavipes: other appendages of this kind are for a less destructive purpose - to keep the tibia when folded in its place. This seems to be the use of the serratures and spine that arm the thigh of Bruchus Bactris, or the Hymenopterous genera Leucospis, Chalcis, &c.; in Onitis Aygulus a short filiform horn arms the humerus, and a longer crooked one that of many species of Saurus^f. In many Stenocori the thighs terminate in two spines, and

Page 670

in Gonyleptes K. the posterior ones are armed internally with very strong ones; with which, as the legs converge at their knee^a, they may probably detain their prey. The knee-pan (Gonytheca) of the thigh, or the cavity at its end, which receives the head of the tibia, is very conspicuous in the weevils; but in no insects more than in Locusta^b, in which tribe it deserves your particular attention.

a	Linn. Trans. xii. t. xxii. f. 16.
b	PLATE XIV. FIG. 5, and XXVII. FIG. 15. r'''.
c	PLATES XIV. XV. XXVII. s''.
d	PLATE XXVII. FIG. 21. s'''. M. Savigny (Anim. sans Vertèbr. 1. i. 46. Note b.) seems to think that this structure obtains in all his Apiropods; viz. the Octopod Aptera, Arachnida, and Myriapoda: but it seems to me evident only in the two tribes mentioned in the text.
e	PLATE XXVII. FIG. 6, 16, 17. t'''.

d. Tibia or Cubitus^c. The tibia or shank is the fourth joint of the leg, which according to the hypothesis lately alluded to is the analogue, in the anteriar leg of the carpus or carpal bones, and in the four posterior ones of the tarsus or tarsal bones of vertebrate animals. This may be called the most conspicuous of the articulations of the leg; for though it is generally more slender and often shorter than the thigh, it fails more under the eye of the observer, that joint being more or less concealed by the body: it consists in general of a single joint ; but in the Araneidæ and Phalangidæ it has an accessory one, often incrassated at its base, which I have named the Epicnemis^d.

With respect to the articulation of the tibia with the thigh - we may observe that in general it is by means of three processes or condyles, two lateral and one intermediate, of the head of the former joint^e: the lateral ones are usually received by a cavity or sinus of the gonytheca