THE ANTHRAX FLY 



days of May arrive it shrivels, and casts its skin; and it is 

 then that the pupa appears, fully clad in a stout, reddish, 

 horny hide. 



The head is round and large, and is crowned on top and 

 in front with a sort of diadem of six hard, sharp, black 

 spikes, arranged in semi-circle. This sixfold plough- 

 share is the chief digging-implement. Lower down the 

 instrument is finished off with a separate group of two 

 small black spikes, placed close together. 



Four segments in the middle of the body are armed on 

 the back with a belt of little horny arches, set in the skin 

 upside down. They are arranged parallel to one an- 

 other, and are finished at both ends with a hard, black 

 point. The belt forms a double row of little thorns, 

 with a hollow in between. There are about two 

 hundred spikes on the four segments. The use of this 

 rasp, or grater, is obvious : it helps the pupa to steady it- 

 self on the wall of the gallery as the work proceeds. 

 Thus anchored on a host of points the brave pioneer is 

 able to hit the obstacle harder with its crown of awls. 

 Moreover, to make it more difficult for the instrument to 

 recoil, there are long, stiff bristles, pointing backwards, 

 scattered here and there among the rows of spikes. 

 There are some also on other segments, and on the sides 

 they are arranged in clusters. Two more belts of thorns, 

 less powerful than the others, and a sheaf of eight spikes 

 at the tip of the body — two of which are longer than the 



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