156 



THE BOOK OF THE ROSE 



CHAP. 



and spare our assistants, though the enemy is in such 

 overwhelming majority that the advice to suspect and 

 destroy all insect life is common and even safest in cases 

 where the friendly forms are unknown. 



Ichneumon flies form one of the strange provisions 

 of Nature for keeping in check the undue increase of 

 insects. These flies lay their eggs in the eggs of moths 

 and butterflies, or in, or on, the bodies of caterpillars and 

 grubs, and thus destroy them. They are of all sizes, 

 some very small, and of so many species that almost 

 every insect has a parasite of this class specially 

 belonging to it. On shoots where aphides have been 

 some time there may often be seen small brown 

 motionless creatures, like aphides solidified and changed 

 in colour. These are aphides which have been pierced 

 by tiny ichneumon flies, whose eggs have hatched in 

 their interior : a magnifying glass will often show a hole 

 in the body from which the new-born fly has emerged. 

 These brown transmogrified aphides are therefore foes 

 transformed into friends — an effort of Nature to assist 

 the negligent Rosarian in dealing with the aphis host. 

 There is no need to allude further to the ichneumon 

 flies, for only the perfect insects are generally seen, and 

 these are not likely to be destroyed, nor, as far as I 

 know, capable of being increased. 



The well-known lady-bird (Coccinellce) in its larva 

 state feeds upon aphides, but I am bound to say that it 

 is not common enough to do much good. You must 

 have a lot of green fly before the prudent ladybird 

 will lay her eggs on the shoot among them, and the 

 careful Rosarian will hope to see nothing of one or 

 the other. Still the shape of the larva, quite unlike 

 that of a Rose-eating grub, and suggesting the perfect 

 insect by its spots, should be noted, that this small 



