THE PLANT-LICE. 235 



Concord, N. H., to whom I am indebted for much valuable 

 information respecting the wheat-fly, or Cecidomyia Tritid, 

 has discovered another pernicious insect in the ears of grow- 

 ing wheat. It seems to agree with the accounts of the Tkrips 

 cerealium, which sometimes infests wheat, in Europe, to a 

 great extent. This insect, in its larva state, is smaller than 

 the wheat maggot, is orange-colored, and is provided with 

 six legs, two antennse, and a short beak, and is very nimble 

 in its motions. It is supposed to suck out the juices of the 

 seed, thus causing the latter to shrink, and become what the 

 English farmers call pungled. This little pest may proba- 

 bly be destroyed by giving the grain a thorough coating of 

 slacked lime. 



Aphides, or plant-lice, as they are usually called, are 

 among the most extraordinary of insects. They are found 

 upon almost all parts of plants, the roots, stems, young 

 shoots, buds, and leaves, and there is scarcely a plant which 

 does not harbor one or two kinds peculiar to itself. They 

 are, moreover, exceedingly prolific, for Rdaumur has proved 

 that one individual, in five generations, may become the 

 progenitor of nearly six thousand millions of descendants. 



It often happens, that the succulent extremities and stems 

 of plants will, in an incredibly short space of time, become 

 completely coated with a living mass of these little lice. 

 These are usually wingless, consisting of the young and of 

 the females only ; for winged individuals appear only at 

 particular seasons, usually in the autumn, but sometimes in 

 the spring, and these are small males and larger females. 

 After pairing, the latter lay their eggs upon or near the 

 leaf-buds of the plant upon which they live, and, together 

 with the males, soon afterwards perish. 



The genus to which plant-lice belong is called Aphis, 

 (Plate III. Fig. 4, Aphis mali^) from a Greek word which 

 signifies to exhaust. The following are the principal char- 

 acters by which they may be distinguished from other insects. 

 Their bodies are short, oval, and soft, and are furnished at 



