APHIS. APHIS. 



Generic Character. 



Rostrum inflexum. 

 Antenna thorace longiores. 

 Alee quatuor erectse, aut 



nullae. 



Pedes ambulatorii. 

 Abdomen postice ssepius 



bicorne. 



Snout inflected. 



Antenna longer than thorax. 



Wings either four upright, 



or none. 



Feet formed for walking. 



Abdomen generally furnish- 

 ed with two horns or pro- 

 cesses. 



JT ROM a great degree of general similarity in 

 the insects of this genus, their true specific charac- 

 ters are often very difficultly determinable. They 

 frequent the leaves, stems, and tender shoots of 

 plants and trees, and are popularly known by the 

 name of Plant-Lice. They are observed to be 

 viviparous in summer, and oviparous in autumn; 

 but the most wonderful part of their history is 

 the power of continued impregnation, through a 

 great many descents, as far as the fifth, eighth, 

 twelfth, and even, according to some observa- 

 tions, the twenty-seventh generation. A pregnant 

 female Aphis, kept by itself, produces perfectly 

 formed young ones, which, though kept separate, 

 will, after a certain period, produce others, which 



