HOW TO KNOW THE IMMATURE INSECTS 



21a. Body straight and of more or less uniiorm diameter throughout; 

 usually 2 spiracles on thorax (pro- and meso-). 

 Fig. 75 Order HYMENOPTERA page 210 



At the present time, at least 120,000 described 

 species are known. The ants, bees and social 

 wasps live in colonies. The larvae vary in form 

 ranging from caterpillar-like sawfly larvae to the 

 legless larvae of bees and ants. They live in nests 

 constituting a colony or are solitary. Most are 

 phytophagous but many are parasitic. Hypermeta- 

 morphosis occurs among many parasitic forms. 

 Gall-makers and leaf-miners are also found among 

 the members of this order. 



Fig. 75. Clover 

 secd-cholcid, 

 Bruchophofus 

 funebris How- 

 ard (U.S.D.A.) 



21b. Body U-shaped with mid-abdominal segments of greater diameter 

 than those near the caudal and cephalic ends; usually with 1 

 spiracle on mesothorax. Fig. 76. ... Order COLEOPTERA page 72 



This is the largest order of insects and comprises 



about 40 percent of all the known members of the 



class Insecta and no less than 264,000 described 



species. The habits of the larvae vary greatly, 



7 ; 7 « k^^y^ most are terrestrial and phytophagous; some ore 



"■ '^- predacious, or carnivorous, or saprophagous; some 



Fig. 76. Large Chest- are aquotic or semiaquatic. Many species are also 



nut weevil, Curcuiie inquilines in the nests and communifies of other 

 probotcidcus Fab. ^ 



(U.S.D.A.) insects. 



22a. With partial (caudal portion non-sclerotized or absent) or com- 

 pleted head capsule 23 



22b. Without a distinct sclerotized head capsule 29 



23a. With partial sclerotiied head capsule 24 



23b. With complete sclerotized head capsule 25 



24a. Mouth parts of normal chewing type and antennae distinct 30 



24b. Mouth parts highly modified, frequently by hook-like mandibles 

 or- apparently absent. Fig. 77 Order DIPTERA page 189 



It includes about 80,000 described 

 species. The larval habits present a 

 great diversity: phytophagous, fungi- 

 vorous, saprophagous, predacious 

 and parasitic. Most are terrestrial. 

 Fig. 77. Spornopoiius fulvus Wied. some aquotic OT semiaquotic. 



42 



