252 



ANNELIDA AND ARTHROPODA: 



ORDER COLEOPTERA (Beetles) 



Diagnosis: minute to large, United States species 

 to two inches long; front wings veinless, thick and 

 leathery, meeting along midline; hind wings sparsely 

 veined and membranous, fold under front wings at 

 rest; some wingless; chewing mouth parts, sometimes 

 on an elongate snout; larvae worm-like, pupa rarely 

 in a cocoon; very numerous, widespread, and with 

 great variation in food habits; both beneficial and 

 detrimental forms (Figure 14.29). 



ORDER STREPSIPTERA (Shepsipteransj 



Diagnosis: relatively few and rarely encountered 

 species; mostly minute; males with tiny front wings 

 and fan-shaped hind wings; females wingless and 

 without eyes or antennae; chewing mouth parts; ex- 

 tremely complex life cycle; females and larvae entirely 

 parasitic on other insects, hosts showing distorted 

 abdomens and perhaps protruding strepsipteran; 

 males sometimes free-living and under rocks (Figure 

 14.29). 



ORDER HYMENOPTERA (Sawflies, Horntails, Bees, 

 Ants, and Wasps) 



Diagnosis: small to moderately large; four mem- 

 branous wings, or none, wings on each side inter- 

 locked during flight, variously held at rest; chewing 

 mouth parts, or chewing-lapping; egg-laying ap- 

 paratus (ovipositor) of female modified for sawing, 

 piercing, or stinging; larvae worm-like, sometimes 

 legless; pupae typically in cocoons; very numerous, 

 include all social insects (bees, wasps, and ants) 

 except termites; widespread, in various habitats; feed- 

 ing habits variable; perhaps most beneficial order of 

 insects, includes many insect parasites and predators, 

 plant pollinators, and the honey bee (Figure 14.29). 



ORDER DIPTERA (Flies) 



Diagnosis: mostly small, minute to moderate 

 sized; two membranous wings or none; hind wings 

 represented by short knobbed structures; piercing- 

 sucking or sponging mouth parts, often drawn out; 

 larvae worm-like, called maggots; very numerous and 

 widespread; many pests and truly dangerous species, 

 larvae often ruin meat, mosquitoes carry malaria and 

 other diseases; some are scavengers, others are insect 

 predators (Figure 14.30). 



Figure 14.30 Diptero, a fly (above, x 4), and Siphoncptera, a flea 

 (below, X 17). (After various sources.) 



ORDER SIPHONAPTERA (Fleas) 



Diagnosis: minute; wingless; sucking mouth parts; 

 bodies laterally compressed, legs specialized for 

 jumping; larvae minute, legless; adults periodic ex- 

 ternal parasites of birds and mammals; transmit such 

 truly dangerous diseases as bubonic plague and 

 typhus fever (Figure 14.30). 



SELECTED READINGS* 



Borror, D. J., and D. M. Delong, 1954. Inlroditctwn lo the 

 Study of Insects. Rinehart and Co., New York. 



*See also p, 212. 



