186 INSECTS INJURIOUS TO VEGETATION. 



not fully grown, and unprovided with wings. Usually between 

 the end of July and the middle of August the insects come to 

 their growth and acquire their wings ; but the mischief at this 

 lime is finished, and the plants have suffered so much that all 

 prospect of a second crop of beans, from new shoots produced 

 after the old stems are cut down, is frustrated. These leaf-hop- 

 pers have the same agility in their motions, and kpparently the 

 same habits, as the vine-hoppers ; but in the perfect state they are 

 longer, more slender, and much more delicate. They are of a 

 pale green color ; the wing-covers and wings are transparent and 

 colorless ; and the last joint of the hind-feet is bluish. The 

 head, as seen from above, is crescent-shaped, and the two eyelets 

 are situated on its front-edge. The male has two long recurved 

 feathery threads at the extremity of the body. The length of this 

 species is rather more than one tenth, but less than three twen- 

 tieths of an inch. It may be called Tettigonia FabcB. Probably 

 it passes the winter in the same way as the vine-hopper. 



2. Plant-lice. (^Aphidida.) 



The Aphidians, in which grotvp we include the insects com- 

 monly known by the name of plant-lice, difier remarkably from all 

 the foregoing in their appearance, their formation, and their man- 

 ner of increase. Their bodies are very soft, and usually more or 

 less oval. The females are often without wing-covers and wings ; 

 and the former, when they exist, do not differ in texture from the 

 wings, but are usually much larger and more useful in flight. We 

 may therefore cease to call these parts wing-covers, in all the 

 remaining insects of this order, and apply to them the name of 

 upper wings. 



Some of the Aphidians have the power of leaping, like the 

 leaf-hoppers, from which, however, they differ in having very 

 large and transparent upper wings, which cover the sides of the 

 body like a very steep roof ; and their antennae are pretty long 

 and thread-like, and are tipped with two bristles at the end. Both 

 sexes, when arrived at maturity, are winged, and some of the 

 females are provided with a kind of awl at the end of the body, 

 very different, however, from the piercers of the foregoing in- 

 sects. With this they prick the leaves in which they deposit 



