186 PLANT LICE. 
“The winged viviparous female is yellowish-green, with the 
eyes black, the lobes of the thorax, the honey-tubes and the legs, 
brown. The general appearance of this form is shown in the fig- 
ure, which also brings out well the differences between this species 
and the grain louse. This is most noticeable in the size of the 
honey-tubes as compared with other species, those of the cab- 
bage louse being much smaller and different in shape. 
“Tn the structure of the antenne there is also a great differ- 
ence, for whereas in the grain louse, described later, there are 
but a few sensory pits on the first long joint, in the present species 
they are very numerous all around the segment; those of the 
Fic. 154.—Aphis maidis Fitch; a, winged viviparous female; b, wingless 
viviparous female; c, pupa. After Forbes. 
third and fourth joints being about the same. On the wingless 
forms there is only one large sensory pit on the third long joint, 
and the usual little group on the whip joint. 
“Not only in antennal structure, but even in the structure of 
the beak itself, this species differs from the grain louse. The 
terminal joint is longer; the second simple, without the peculiar 
flap figured in the other species. The beak is also longer, and 
more slender, in contrast with the antennz, which are shorter and 
stouter. 
“This insect has been known in our country since 1791, and 
is as common in Europe as it is in the United States; indeed, it 
is probable that the species has come to us from Europe. 
