1 10 HEMIPTEUA. 



juice which attracts ants and other inimical in- 

 sects. There are often in the same species, and 

 even in the same family, individuals with wings 

 and without wings ; and that without any re- 

 spect to the difference of sex. But the males 

 are in general much smaller than the females, 

 and also less numerous. They seldom appear 

 before autumn, when they impregnate their 

 females, who soon after lay eggs, or rather a 

 sort of capsules, in which the young Aphides 

 lie, already perfectly formed, but do not break 

 their shell till the following spring. When they 

 appear it is very remarkable that they are almost 

 wholly females, with hardly a male to be seen 

 during the w T hole spring and summer. Not- 

 withstanding this, all thesefemale Aphides with- 

 out any communication with a male are able 

 to propagate their species ; and seem to have 

 received the genial influence, not merely for 

 themselves alone, but for their posterity to the 

 ninth generation. During the whole summer 

 they are viviparous, and if a young Aphis is 

 taken, immediately upon exclusion from the 

 mother, and kept apart, it will produce young ; 



