APHIS. APHIS. 
Generic Character. 
nostrum inflexum. 
Antenna thorace longiores. 
Ala quatuor erectae, aut 
nullae. 
Pedes ambulatorii. 
Abdomen postice saepius 
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. 
From 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 
