278 BEES AND BEE-KEEPING. 



depositing eggs in the Aphis of the rose, the parsnip, 

 the willow, the plum, the peach, and many others. 

 We may also reckon as allies many tiny Ichneumon 

 flies, which persistently attack Aphides not much 

 smaller than themselves. The female deposits from 

 one to five eggs within the body of the Aphis. The 

 resulting grubs live on the food assimilated by the 

 host, whose vital organs, with much consideration, 

 they do not invade until the last moment. His ex- 

 ternal skin they leave, as this forms a case, within 

 which they pass through their pupal change. Aphi- 

 dins Rosae, Beckton tells us, he watched " for some 

 time, as two individuals seated themselves upon the 

 backs of Aphides, seeming to enjoy the contortions 

 made to throw them off. After about five minutes, 

 the ovipositor was inserted by a sort of thrust, when 

 the flies made away in pursuit of other game." As 

 the grub within develops, the Aphis visibly undergoes 

 an abnormal modification, the skin at last hardening 

 into a globular, horny box, within which the perfect 

 parasitic Ichneumon is formed, and at last escapes 

 by carving a circular hole. These cases, pierced and 

 empty, may constantly be seen under rose leaves. 

 Curiously enough, the above-mentioned changes are 

 often interrupted by a second parasitic attack, another 

 egg or eggs being deposited within the first parasitic 

 larva, so that it, in turn, succumbs, and another form 

 of life presents itself. How endless the interchanges 

 of life and death ; respecting which the philosopher is 

 not much in advance of the humorist, who says — ■ 



"Larger fleas have lesser fleas upon their backs to bite 'em, 

 And these, again, have smaller fleas, and so ad infinitum." 



