APHIDES. 



395 



Leaf of the Currant-hush, bulged out by the Aphis ribes. 



which we have seen, occurs on the leaves of the elm, 

 and is caused by the Aphis ulmi. The edge of an 

 elm-leaf inhabited by those aphides is rolled up in 

 an elegant convoluted form, very much like a spiral 

 shell; and in the embowered chamber thus formed, 

 the insects are secure from rain, wind, and, partially, 

 from the depredations of carnivorous insects. One 

 of their greatest enemies, the lady-bird {Coccinella)y 

 seldom ventures, as we have remarked into con- 

 cealed corners, except in cold weather, and contrives 

 to find food enough among the aphides which feed 

 openly and unprotected, such as the magpie aphides 

 of the alder [Aphides sambuci). The grubs, how- 

 ever, of the lady-bird, and also those of the aphidi- 

 vorous flies, {Sijyyhi)^ may be found prying into the 

 most secret recesses of a leaf, to prey upon the inna- 



