372 TEXT-BOOK OF ZOOLOGY 



aid to the insect. The first abdominal somite having the form of a thin 

 stalk, the animal is able to approach the tip of the abdomen to the 

 opening of the mouth. (How are these arrangements also of advantage 

 to ants provided with a sting ?) 



(b) Enemies. Woodpeckers, wrynecks and ant-lions consume large 

 numbers of red ants, and also of other species, but their chief enemy 

 is to be found within their own ranks, just as man's chief enemy is 

 man. An eternal war is waged between the separate communities : an 

 ant with the "scent" of an alien nest (see bee; the organs of sense 

 are placed in the elbowed antennce) is at once attacked, killed and 

 devoured. The same treatment is dealt out to the larvae and pupae of 

 foreign nests when an opportunity offers itself. (Some species of ants 

 do not devour the captured larvae and pupae, but rear from them a band 

 of helpmates or slaves, whom they compel to work for them. Indeed, 

 some ants can no longer exist without slaves, their mandibles being only 

 adapted for fighting, but no longer for feeding. Some (chiefly foreign) 

 species actually undertake well-ordered slave-raiding expeditions. 



G. The Ant in its Relations to Man. 



As an industrious destroyer of many noxious insects (pine-moth 

 caterpillars, bark beetles, etc.), the red ant is most useful to man, and 

 we ought therefore not to rob it of its pupae (uspd as food for goldfish 

 and cage birds), or drown the insects by thousands in alcohol (formic 

 alcohol). Those species, on the other hand, which attack fruit and 

 grapes or protect the injurious aphides, and pilfer all sorts of sweet 

 delicacies in our houses, must be regarded as destructive or troublesome 

 creatures. Ants render no service in the fertilization of flowers (see 

 bee) on account of their body being thin and smooth. Indeed, many 

 plants protect themselves (by what means ?) against the visits of these 

 unwelcome pilferers. 



Sub-Order 2 : Provided with a Boring Organ (Terebrantia). 



Families: Ichneumon Flies (Ichneumonidae) ; Gall Flies (Cyni- 

 pidae); Saw Flies (Tenthredinidae) and Wood Wasps (Uroceridae). 



f 



1. Among the caterpillars of the white cabbage butterfly, which 

 ascend planks, walls, etc., to enter into the pupa stage, we always notice 

 some which are dead and surrounded by small yellow egg-like bodies. 

 From each of these supposed " caterpillar's eggs " there escapes in the 

 following spring a black fly about J inch long, an Ichneumon Fly of the 



