Insect morphology least three different positions: prognathous, opisthognathous, and hypognathous. In species with prognathous articulation, the head is positioned vertically aligned with the body, such as species of Formicidae; while in a hypognathous type, the head is aligned horizontally adjacent to the body. An opisthognathous head is positioned diagonally, such as species of Blattodea and some Coleoptera. The mouthparts vary greatly between insects of different orders, but the two main functional groups are mandibulate and haustellate. Haustellate mouthparts are used for sucking liquids and can be further classified by the presence of stylets, which include piercing-sucking, sponging, and siphoning. The stylets are
Insect morphology the fundamental distinction is often blurred, as fold lines may permit some flexibility or vice versa. Two constants, found in nearly all insect wings, are the claval (a flexion line) and jugal folds (or fold line), forming variable and unsatisfactory boundaries. Wing foldings can very complicated, with transverse folding occurring in the hindwings of Dermaptera and Coleoptera, and in some insects, the anal area can be folded like a fan. The four different fields found on insect wings are: Most veins and cross-veins occur in the anterior area of the remigium, which is responsible for most of the flight, powered