178 A BOOK OF INSECTS 



preyed upon by so many kinds of insects that but for 

 their inexhaustible powers of reproduction their race 

 would assuredly be stamped out. Among their chief 

 enemies are the lace-wing and golden-eye flies of the 

 order Neuroptera. These usually lay their curious stalked 

 eggs in the vicinity of an aphid colony, upon the members 

 of which the active larvae begin to prey as soon as they 

 are hatched. When full-fed, each larva spins an almost 

 spherical cocoon, which appears remarkably small when 

 compared with its maker, and with the perfect insect 

 which eventually makes its debut through a small hole 

 to which the cover remains attached like a lid. By what 

 art this triumph of packing is accomplished remains a 

 mystery. 



Two other groups are notably dependent upon aphides 

 for food. These are the ladybird beetles (Cocciuellidce) 

 and a section of the hover-flies (Syrphidcs). The latter 

 abound in gardens, where the adults frequent flowers and 

 feed upon pollen. The females may often be seen engaged 

 in their task of oviposition. They make sudden darts at 

 buds and stems, and lay their eggs singly among the 

 crowded pests, so that each larva may have a happy 

 hunting ground of its own. "When one watches a hover-fly 

 poised before an infested spray, one is tempted to believe 

 that she is engaged in a deliberate calculation as to the 

 number of larvae its flocks and herds will support. The 

 larvae, which are not unlike little leeches in appearance, are 

 insatiable in their assaults upon green-fly and other small, 

 soft-bodied insects. Their manner of feeding is peculiar. 

 They rear themselves up on their tails, lash wildly about, 

 and suddenly seize an aphid by means of their hooked 

 mouth-parts. The aphid is then deliberately pulled from 

 its hold upon the plant, and held aloft, where its struggles 

 for liberty are of no avail. It is then rapidly sucked dry ; 



