THE CABBAGE APHIS. 171 



plants. They then commence the business of hunting 

 for their natural food, and continue it through their 

 different stages. 



The larva of the Ladybird, if viewed through a power- 

 ful lens, is a singularly repulsive-looking creature, the 

 jaws being long and powerful. Curtis, in his well-known 

 Farm Insects^ thus graphically describes their method 

 of feeding: — "Their method of attacking the aphides is 

 curious. I have seen one of the latter struggling while 

 this little insect-alligator threw his fore-legs about it, and 

 was greatly amused at the skill exhibited; for, fearing 

 that the aphis might escape, it gradually slid along to 

 the wings, which were closed, and immediately began to 

 bite them, so that in a short time they were useless, being 

 matted together. It then returned in triumph to the side 

 of its helpless victim, and, seizing the thorax firmly in its 

 grasp, it ate into the side, coolly putting one of its hind 

 legs over those of the aphis, whose convulsive throbs 

 annoyed its relentless enemy." 



The Ladybirds are more useful, however, on fruit trees, 

 as they can the easier hide from sparrows, which brutes 

 are, unfortunately, very partial to these useful little 

 insects. 



Many Ladybirds are destroyed by the unthinking popu- 

 lation, or else from a want of knowledge as to their 

 usefulness to growers in any clime and in any country. 



The so-called Syrphid flies, alluded to previously, are 

 great destroyers of aphides. This fly has a proboscis not 

 unlike that of a meat-fly, the proboscis, which is pointed, 

 being terminated by two large lips, and enclosing the 

 sucker in a groove. The larva is soft, and mostly yellow. 

 Its body is divided by rings (see Fig. 13), and tapers in 

 form, the anterior position being the narrowest, and thus, 

 according to Mr. Gibbons, one of our very best micro- 

 scopists, it attacks its aphis prey. It crawls along with ease 

 and tolerable rapidity, but frequently attaches itself to a 

 leaf by a glutinous substance, which it has the power of 

 secreting. It then turns itself backward and forward, 

 surveying the country until it meets with an aphis. It 



