106 DESTROYERS OF APHIDES. 



example of this parasite upon parasite. (Plate x., fig. 14, 

 Colax dispar.) 



In part verification of the lines : 



" Great fleas and little fleas have smaller fleas to bite 'em, 

 The smaller fleas have lesser fleas, so on ad infinitum." 



Quoted in Stephens' Illustrations, vol. vii. 



(422.) There is another set of hymenopterous insects, 

 which seize upon Aphides and carry them off to their 

 habitation to feed their own children. It is said that thou- 

 sands are thus killed. Examples of this order, which per- 

 form this friendly office to man, are to be found in the 

 genera of Psen, Diodontis, Pemphredon, and Tropoxylon. 

 (Plate x., figs. 1, 2, 13, 15.) 



(423.) I have no doubt that the omnivorous and greedy 

 wasp would have no objection to eat Aphides, if he could 

 get nothing better. I formerly tried to press two or three 

 colonies of wasps into my service, to make skeletons of 

 small animals, but their voraciousness was so great, that 

 they not only ate the flesh but the bones also. 



(424.) I very much suspect that the earwing is a great 

 devourer of Aphides, although it is stated that it is entirely 

 a vegetable feeder. When I have gone at night with a 

 lantern to see what the Aphides were about, I have fre- 

 quently observed numbers of earwings very busy at the 

 places where the Aphides greatly abounded, but I have not 

 actually seen them devour them. There is a very beauti- 

 ful Acarus which is always to be found in company with 

 the Aphides. He seizes the Aphis, and appears to suck its 

 juices. (Plate v., fig. 9.) 



(425.) Numbers of black and other spiders doubtless 



