SUBDIVISION OF INSECTA PTERYGOTA INTO SUBORDINATE GROUPS

Abstract

THE acquisition of wings is the most important factor upon which the unparalleled progressive evolution of insects depends. The development of liquid food feeding, though of great moment, plays only a subordinate part as compared with flight. Every order of the Insecta Pterygota shows its own type of wing, and the wing venation serves as a well-established systematic criterion, yet the functional significance of the almost endless variations in venation is as yet scarcely perceived. On the other hand, the musculature of wings shows considerable constancy in the majority of Pterygote orders, its principal modifications being few and functionally comprehensible. Therefore an attempt seems desirable to use 'the muscular motor of the wing' as a taxonomic criterion, especially for the much-needed grouping of insect orders into larger units.