I

Ileum. - The proximal end of the small intestine. (Gr. eilo, to roll.)

Imagal, Imaginal. - Pertaining to the imago. (L. imago.)

Imago. - The perfect state of the insect. (L. the image.)

Imaginal buds. - Rudiment-groups of cells from which arise the organs of the imago during pupation; and which may be seen in the larva. (From L. imago, and Du. bot, a bud.)

Imbricate. - Overlapping one another, like tiles on a roof. (L. imbrex, a gutter-tile, from imber, a shower.)

Imperfect. - Not complete or perfect; unfinished. (L. im=in, not, and perfectus, finished.) See Incomplete metamorphosis.

Impression. - Punctuation; any marking upon the surface; an indentation; a depression. (L. impressare, from imprimere, to press upon.)

Impunctate. - Without punctuation. - (L. in, not, and punctum, to prick.)

In-. - A Latin prefix signifying in, into, on, not, etc.

Inaurate. - When striæ or other impressed parts have a metallic splendour. (L. in, and aurum, gold.)

Incanus. - White, with a small proportion of black; grey. (L. incanus, grey.)

Incased. - (Pupæ.) (L. in, and O.F. casse, L. capsa, a box, cover, L. capere, to hold.) See Pupæ folliculatæ.

Incised. (Incision.) - Cut into equal marginal segments. (L. incisus, pa. par. of incisere, to cut into.)

Incisura axillaris. - (Wing.) The axillary incision which terminates the posterior angle towards the base of the wing. (L.)

Incisure. - A deep incision between the segments, when they recede from each other. (L. incisus.)

Incomplete metamorphosis. - When there is no quiescent or sealed-pupal state in the life history of an insect. When histolysis does not take place. (L. in, and completus, complete; and metamorphosis.)

Inconspicuous. - Not easily discernible. (L. in, con, and specio, to see.)

Incrassate, Incrassated. - Thickened. (L. in, and crassus, thick.)

Incrassate. - Having the margin rounded and swollen. Disproportionately thick in part. (L. in, and crassus.)

Incumbent. - (Wings.) Those wings, which, when the insect is at rest, cover the back of the abdomen horizontally. Resting against. One lying over the other. (L. incumbo, to lie down.)

Incunabulum. - Cocoon, the case in which the pupa reposes, and which has been artificially prepared by the larva. (From L. incunabula, cradle, birth-place, origin.)

Incurved. - Bowed inwards. (L. incurvo.)

Indurated. - Hardened. (L. induro, to harden.)

Indusium. - The membrane found between the serosa and the amnion. The case or covering of certain larvæ. (L. indusium, an undergarment.)

Inermis, Inermous. - Unarmed, destitute of striæ, spines, and all sharp processes. (L.)

Inferior (antennæ inferiores). - (Antennæ.) Placed beneath the head. (L. comparative of inferus, low.)

Inferior Lobe. - (L. inferus, and Gr. lobos.) See Lobus Inferior.

Inferior region (regio inferior). - (Wing.) (L. inferus, and region, from, L. regio.) See Costal region.

Inflated (capitulum compositum). - (Antennæ.) Having the knob of a capitate antenna in the form of a bladder. (L. in, and flo, to blow.)

Inflected. - Bent inwards at an angle. (L. inflecto, to curve.)

Infra-anal flaps. - The podical plates (Packard.) (L. infra, underneath, and anus.)

Infra-anal lobe. - A thick, conical, fleshy lobe, often ending in a hard, chitinous point, and situated directly beneath the vent. (Packard.)

Infra-buccal cavity. - A short compressed buccal tube, dilated ventrally to form a spheroidal sac, situated in the mouth of Ants, and used as a receptacle for the fine particles of food rasped off or picked up by the tongue. (L. infra, and bucca, the mouth.)

Infracted. - Bent inwards abruptly, as if broken. (L. in, and frango, to break.)

Infra-ocular (ant. infra-oculares). - (Antennæ.) Inserted beneath the eyes. (L. infra, underneath, and oculus, an eye.)

Infumated. - Clouded, as if smoked; coloured like smoke. (L. in, and fumus, to smoke.)

Infundibulate, Infundibuliforme. - Having the shape of a funnel. (L. infundibulum, a funnel.)

Infuscate, Infuscated. - Darkened, with a blackish tinge. (L. in, and fuscus, dark.)

Ingluvies. - The Crop. (L.)

Ingurgitation. - The act of swallowing. (L. ingurgito, to soak in.)

Inner. - Interior; nearer to the centre. (A.S. innera.)

Inner angle. - (Wing.) The angle situated at the junctions of the outer edge and the inner edge.

Inner edge. - (Wing.) The interior angle. The extreme border running from the inner angle to the insertion of the wing in the thorax.

Inner margin, Interior margin. - (Wing.) The margin which extends from the base to the posterior angle.

Inocular (antennæ inoculares). - (Antennæ.) When the eye surrounds the base of the antennæ. (L. in, and oculus, an eye.)

Inosculation. - [See Anastomosis.] [PM]

Inquiline. - A dweller in the nest of an alien species. (L. inquilinus, a tenant.)

Inquilines. - The term given to those insects (species of Cinipidæ) which do not make galls, but deposit their eggs in galls already formed, and live in the gall tissues, killing the gall-maker as a rule. (L. inquilinus, a tenant.)

Insecta, Insect. - The class Hexapoda; articulated animals with a body composed of three distinct parts, the head, the thorax, and a segmented abdomen. (L. in, and seco, sectum, to cut.)

Insectivorous. - Subsisting on insects. (Insect, and L. voro, to devour.)

Insectum, Insecte, Insect. - The derivation of the terms from the two large incrassated masses the thorax and the abdomen. (L. insectum, literally “a thing cut into,” i.e. nearly divided, from the shape. - L. insectus, past participle of insecare, is cut into. - L. in, into; secare, to cut.)

Inserted. - (Head.) When it is partly, particularly the occiput, concealed, within the thorax. (L. in, and sero, sertum, to join.)

Insertio of Maxilla. - The lowest portion of the maxilla adjoining the head. (L. in, and sero, sertum, and maxilla, cheek-bone, chin.)

Insertio of Labium. - The lowest portion of the labium adjoining the head. (L. in, and sero, sertum, and labium, lip.)

Insertion Insertio. - The point of attachment of movable parts. (L. in, and sero, sertum, to join.)

Insertum. - (Head.) (L. in, and sero, sertum.) See Inserted.

Instar. - The new stage after moulting, and casting of skin. (L. instar, image; form, figure, etc.)

Institia. - Striæ of equal breadth throughout.

Instrumenta cibaria. - The mouth parts. (L. instrumentum, and cibarius, of food.) See Partes oris.

Instrumenta cibaria libera. - (L. instrumentum, cibarius, and liber, free.) See Instrumenta cibaria mordentia.

Instrumenta masticandi. - The masticating organs, another name for Instrumenta cibaria mordentia. (L. instrumentum, and from mando, to masticate.)

Instrumenta cibaria mordentia. - The biting organs; the Mandibles. (L. instrumentum, cibarius, of food, and from mordeo, to bite.)

Instrumenta cibaria suctoria. - The sucking mouth; the haustellum. (L. instrumentum, cibarius, and suctus, sucking.)

Inter-. - A Latin prefix signifying among, or between.

Intercalary segment. - The third segment of the head, tritocerebral. [PM]

Interior. - Within; internal; within any limits; the opposite to exterior; the inside. (L. intra, within.)

Interior edge, Inner edge. - (Wing.) The boundary of the inner margin.

Interior margin. - (Wings.) The inner margin.

Interior palpi. - The labial palpi.

Intermaxillaire. - The maxillary lobe. (L. inter, and maxilla, the jawbone, jaw.) See Lobus maxillæ.

Intermediate Area. - That part of the wing lying between the costal area, and the anal area. (L. inter, medium, and area.)

Internal Chiasma. - The chiasmatic fibres of the internal medullary mass.

“Internal hairs” (?). - Internal hair-like bodies, arising from the fold of the tænidia and projecting into the lumen of the tracheæ. (Stokes.)

Hollow hair-like structures communicating with the tænidia from which they arise by an enlarged base, ending in a fine - sometimes bifid or trifid - point. (Packard.)

Internal Medullary Mass. - The opticon, which connects with the median part of the procerebrum by direct fibres to form the optic nerve or tract.

Internal maxillary palpi. - (L. internus, maxilla, and palpi.) See Palpi maxillares interni.

Internal paramera. - The inner pair of genital appendages of the Male; they are closely applied to each other, and function as a penis.

Inter-ocular (antennæ interoculares). - (Antennæ.) Placed between both eyes. (L. inter and oculus.)

Interrupted. - Suddenly stopped; broken; intermittent. (L. inter, and ruptum, to break.)

Interstices. - Spaces between striæ, or rows of punctures on the elytra. Spaces between things closely set. (L. inter, and status, a position.)

Interstitial line. - The longitudinal space which intervenes between two striæ of the elytra. (L. inter, and status.)

Intervals. - Spaces between the striæ, or rows of punctures on the head and thorax. (L. inter, and vailum, a rampart.)

Interventricular valvule. - A minute valve working in conjunction with the auriculo-ventricular opening of the Dorsal vessel. (L. inter, ventriculus and valva.)

Intestina parva. - The small intestine. [See Intestines.] (L. intus, within, and parvus, small.)

Intestines. - A tube uniting with the stomach, and consisting of two portions, the small intestine or intestina parva, and the terminal intestine, or rectum. They are never subject to the convolutions so general in vertebrata. (There are several long tortuous filiform appendages originating from the stomach, or near its union with the intestines, which are said to be bile vessels corresponding with the liver of vertebrata.) (F. intestin, from L. intestinus, inwards, from intus, within.)

Intima. - The endotrachea.

Intorted. - Turned or twisted inwards. (L. in, and torqueo, to twist.)

Intricate. - When elevations are placed irregularly and close together, or involved, or complicated. (L. in, and tricæ, hindrance.)

Intro-. - A Latin prefix signifying to, within.

Intromittent organ. - [See Ædeagus, Penis.] [PM]

Introrsum. - (Direction). Inwards; introrse, turned inwards. (L.)

Invaginate. - To form a pocket by turning in. [PM]

Invertebral, Invertebrate. - Destitute of the vertebral or spinal column. (L. in, and vertebra, a joint.)

Involuted. - Rolled inwards spirally. (L. involvo, to roll to, or upon.)

Involvulus. - A caterpillar that wraps itself in leaves. (L.)

Iridescent. - Exhibiting prismatic colours, like those of the rainbow. (L. - Gr. L, iris - Gr. iris, iridis, the rainbow. Ders. irid-esc-ent, irid-ium; from irid-, stem of iris.)

Iridicolorous. - Reflecting prismatic hues, iridescent. (Gr. iris, and L. color.)

Iris. - The circle of colour which encloses the pupil of an eye of colour. (Gr. iris, iridis, the rainbow.)

Iris tapetum. - [See Pigment.]

Irregular (irregulares). - (Antennæ.) Having all the joints different in shape. (L. in, and regularis, according to rule.)

Irrorate, Irrorated. - Freckled; covered with atomi. (L. irroro, irrorare, to bedew, drop upon.)

Islet. - A spot of different colour, included in a plaga, or macula. (Fr. île, from L. insula.)