INSECTS. 



141 



the summer months. It is an exudation proceeding from the 

 larva of a little insect (Aphrophora spumaria), and affording 

 it, at the same time, concealment from enemies and pro- 

 tection from vicissitudes of weather. 



Fig. 129. LARVA OF APHIS 

 (MAGNIFIED). 



Fig. 130. Arms (MAGNIFIED). 



The minute insects which are black upon the woodbine, 

 green upon the rose, and which have a cottony appearance 

 upon the apple-tree, are all of them different species of 

 Aphides or plant-lice (Figs. 129, 130). 



"A feeble race, yet oft 



The sacred sons of vengeance, on whose course 

 Corrosive famine waits, and kills the year." THOMSON. 



When very numerous, they weaken and occasionally de- 

 stroy the plants on the juices of which they subsist. The 

 saccharine fluid of which the Ants are so fond is secreted by 

 the Aphides ; they are preyed upon and destroyed by insects 

 of other orders. The most remarkable circumstance connected 

 with their history, is their extreme fecundity, and the singular 

 provision for the preservation of the race from year to year. 

 A common species which infests the apple, and is known as 

 the American Blight (Aphis lanigwd), produces, in the course 

 of a season, eleven broods of young. The first ten broods arc 

 viviparous, or are brought forth aiive, and consist entirely of 

 females. These never attain their full development as perfect 

 insects ; but, being only in the larva state, bring forth young, 

 and the virgin Aphides thus produced are endowed with 

 similar f&imdity. But at the tenth brood this power ceases. 



