248 HEMIPTERA. 



young of various two-winged flies belonging to the genus 

 Syrphus. Many of these flies are black, with yellow bands 

 on their bodies. I have often seen them hovering over small 

 trees and other plants, depositing their eggs, which they do 

 on the wing, like the bot-fly, curving their tails beneath the 

 leaves, and fixing 'here and there an egg, wherever plant-lice 

 are discovered. Others lay their eggs near the buds of trees, 

 where the young may find their appropriate nourishment as 

 soon as they are hatched. 



The young are maggots, which are thick and blunt behind, 

 tapering and pointed before ; their mouths are armed with a 

 triple-pointed dart, with which they pierce their prey, elevate 

 it above their heads, and feast upon its juices at leisure. 

 Though these maggots are totally blind, they are enabled to 

 discover their victims without much groping about, in con- 

 sequence of the provident care of the parent flies, which 

 leave their eggs in the very midst of the sluggish lice. 

 Mr. Kirby says, that, on examining his currant-bushes, which 

 but a week before were infested by myriads of aphides, not 

 one was to be found ; but beneath each leaf were three or 

 four full-fed maggots, surrounded by heaps of the slain, the 

 trophies of their successful warfare. He also says that he 

 has found it very easy to clear a plant or small tree of lice, 

 by placing upon it several larvae of Coccinella or Syrphi. 



3. Bark-lice. ( Coccidce.) 



The celebrated scarlet in grain, which has been employed 

 in Asia and the South of Europe, from the earliest ages, 

 as a coloring material, was known to the Romans by the 

 name of Coccus, derived from a similar Greek word, and 

 was, for a long time, supposed to be a vegetable production, 

 or grain, as indeed its name implies. At length it was 

 ascertained that this valuable dye was an insect, and others 

 agreeing with it in habits, and some also in properties, hav- 

 ing been discovered, Linnaeus retained them all under the 

 same name. Hence in the genus Coccus are included, not 



