imbricated                                        Overlapping.

imago                   A adult insect.

incrassate antenna                        An antenna in which the antennomeres gradually increase in width towards the apex or increase and subsequently decease in width. When the increase is marked, the antenna looks club-like and is often called clavate.

inquiline                                         Animal that shares a home with a unrelated animal with no apparent adverse effect on the animal.

integument                                       Outer cuticle or epidermis of insect and helminthes.

instar                                                   Stages of growth, each separated by a moult.

intercalary vein                              Longitudinal vein arising from the wing margin inwards but not connecting with any main veins.

intercoxal process                         (of abdomen). See Abdominal process

intercoxal process                         (of prosternum). See Prosternal process

interfacetal setae                           (of eye). Setae arising between adjacent eye face         .

invagination                            To fold in so that an outer becomes an inner surface.