250 HEMIPTERA. 



the head upwards, and sticking by their flattened inferior 

 surface closely to the bark. On attempting to remove them 

 they are generally crushed, and there issues from the body 

 a dark-colored fluid. By pricking them with a pin, they 

 can be made to quit their hold, as I have often seen in the 

 common species, Coccus Hesperidum, infesting the myrtle. 

 A little later the body is more swelled, and, on carefully 

 raising it with a knife, numerous oblong eggs will be dis- 

 covered beneath it, and the insect appears dried up and 

 dead, and only its outer skin remains, which forms a convex 

 cover to its future progeny. Under this protecting shield 

 the young are hatched, and, on the approach of warm weath- 

 er, make their escape at the lower end of the shield, which 

 is either slightly elevated or notched at this part. They 

 then move with considerable activity, and disperse them- 

 selves over the young shoots or leaves. 



The shape of the young Coccus is much like that of its 

 parent, but the body is of a paler color and more thin and 

 flattened. Its six short legs and its slender beak are visible 

 under a magnifier. Some are covered with a mealy powder, 

 as the Coccus Cacti, or cochenille of commerce, and the 

 Coccus Adonidum, or mealy bug of our greenhouses. Others 

 are hairy or woolly ; but most of them are naked and dark- 

 colored. These young lice insert their beaks into the bark 

 or leaves, and draw from the cellular substance the sap that 

 nourishes them. 



Rdaumur observed the ground quite moist under peach- 

 trees infested with bark-lice, which was caused by the drip- 

 ping of the sap from the numerous punctures made by these 

 insects. While they continue their exhausting suction of 

 sap, they increase in size, and during this time are in what 

 is called the larva state. When this is completed, the in- 

 sects will be found to be of different magnitudes, some much 

 larger than the others, and they then prepare for a change 

 that is about to ensue in their mode of life, by emitting from 

 the under side of their bodies numerous little white downy 



