LIBRARY

56
COLLEGE ENTOMOLOGY
25. One pair of wings present. 2H
Two pairs of wings present 28
26. Abdomen with caudal filaments 27
Abdomen without. caudal filaments. (Flies.) DIPTERA p. 728
27. Halteres, or small knobbed organs representing the hind wings, absent;
wings with many veins. (Few Mayflies.) EPHEMERIDA p.211
Halteres present; wings with a simple forked vein; minute fragile insects
llsually with two terminal abdominal filaments. (Male Coccids:
HOMOPTERA.) . HEMIPTERA p. 263
28. Fore and hind pairs of wings unlike in structure, the fore pair thickened,
leathery or horny, the hind pair membranous. 2H
Fore and hind pairs of wings alike in structure; membranous 35
29. Fore wings reduced to slender club-shaped appendages; very small
and rather rare insects. (Strel1sipterans.) . STREPSIPTERA p. 609
Fore wings with bases thickened and frequently opaque and the apical
portions membranous; mouth parts for piercing and sucking.
(Bugs.) . HEMIPTERA p. 263
Fore wings of the same texture throughout. 80
30. Fore wings leathery or homy, without veins, and functioning as covers
of the hind wings 31
Fore wings leathery or parchment-like with a network of veins; hind
wings folded fan-like beneath the fore pair . :32
31. Fore wings short and never entirely covering the abdomen; abdomen
terminating in a pair of movable forceps. (Earwigs.) DERMAPTERA p. 131
Fore wings partially or completely covering the abdomen; abdomen
without terminal forceps. (Beetles, Weevils.) . COLEOPTERA p.518
32. Hind femora usually enlarged for jumping (in GRYLLOTALPIDIE
or mole crickets the hind legs are normal whereas the forelegs are
broad and fossorial); body somewhat cylindrical or compressed
laterally; wings held more or less roof-like in repose; tergites usually
larger than the sternites; stridulating organs present. (Grasshoppers,
Katydids, Crickets.) . ORl'HOPTERA p. 87
Hind femora not enlarged for jumping; body somewhat compressed
dorsally; wings resting flat over the body; tergites and sternites subequal;
stridulating organs absent . 33
33. Body elongate; head free and uncovered; slow-moving insects . 34
Body oval and flattened; head partially or wholly concealed beneath
the pronotum; swift-running species. (Cockroaches.). BLATTARIA p. lOH
34. ProthoralC greatly elongated; forc1egs raptorial or specialized for
catching and holding living prey; cerci usually more than one-segmented.
(Mantids.). . MANTODEA p. 124
Prothorax short; legs similar; cerci simple; stick-like or leaf-like insects.
(Walkingsticks, Leaf Insects.) . . PHASM]DA p. 116
35. Last tarsal segment terminating in a bladder-like organ, without well-defined
claws; wings usually fringed with hairs. (Thrips.) THYSANOPl'ERA p. 247
Last tarsal segment terminating in well-developed claws. 36
36. Wings partially or more often entirely covered with scales; mouth
parts for sucking. (Moths, Butterflies.) . LEPIDOPTERA p. 421
Wings transparent or but thinly clothed with hairs 37