INSECTS. 



129 



should decompose, while, on the other hand, a living 

 animal would not allow itself to be buried, the wasp 

 first brings the insect into a condition in which it 

 cannot make any voluntary movements. For this 

 purpose most species sting the captured prey several 

 times in the body, and thus often injure the ventral 

 ganglia (p. 84) ; by this treatment the insect is not 

 killed, but reduced to a condition of apparent death. 

 Most digging wasps are useful, since they chiefly bury 

 destructive kinds of insects. The Common Sand Wasp 

 {AmmophUa sabulosa, Fig. 89), buries caterpillars. 



Fig. 89. — The Common Sand Waap (^AmmopMla saUilosa') ; natural size. 



the Path Wasp (Pompilius viatious), spiders; the 

 Weevil-killing Sand Wasp (Gerceris arenaria) and the 

 Fly-killing Sand Wasp (Mellinus arvensis) respectively 

 bury weevils and flies. 



Family: Formicidae (Ants). 



Large strong mandibles adapted for biting ; maxillae 

 and lower lip not prolonged like a proboscis. Workers 

 wingless; the males and reproductive females have 

 weakly veined wings. In correspondence with these 

 facts, the mesothorax which bears the larger wings 

 is most strongly developed in the last, but the 

 prothorax in the workers. Abdomen united with the 

 thorax by a one- (Formica) or two-jointed (Myrmica) 

 stalk. All female ants, and naturally workers too, 

 possess poison-glands, the secretion of which accu- 

 mulates in a poison-bladder ; but the sting is lacking 

 in all species of Forinica. The stingless ants ie.g. 



K 



