70 
Phorodon humuli. Schrank. The Hop Aphis. 
Our species is probably identical with the Hop Aphis, of Europe, 
as no appreciable differences between the characters of the two can be 
observed. 
This is, perhaps, one of the most injurious of the family, in some 
instances almost entirely destroying the hop crop. As an indication 
of the immense loss which it sometimes occasions, we mention the fact 
that in England it occasioned, in a single year, a loss of over $400,000 
on excise duty on hops; in other years since that time the loss has 
been even much greater. 
On account of its injurious effect upon this important crop, I give 
a more extended description of its various stages, and a fuller account 
of its habits, than I have usually done with reference to the other 
species. 
The larvae , or young lice, are of a transparent yellowish white color, 
with black eyes, but as they increase in age and size, they change to 
green. 
The pupa .—Green throughout, and slightly pilose, the head and 
thorax broad and squarish; on the top of the head are two red dots 
which mark the spots where the ocelli will appear. Even while in 
the larvae state the interior prolongations of the antennal tubercles are 
very prominent, and the gibbous form of the first joint is very appar¬ 
ent. At the time they commence to enter the pupa state the abdo¬ 
men assumes an oblong shape with the sides parallel; after the wing- 
cases appear the oval form begins to be assumed. Eyes red. 
Wingless viviparous female .—It is small, oval in form, and pale 
green throughout; eyes red. Antenna? somewhat shorter than the body; 
legs of moderate length; honey-tubes long, extending beyond the tip 
of the body, cylindrical; tail very short and conical; the tubercles and 
first antennal joints as described. Slightly deeper green spots are 
sometimes seen on the back; but the usual green color prevails through¬ 
out all the parts. 
Winged viviparous female .—General color pale green. Antennae 
about as long as the body, greenish at base, apical portion dusky; eyes 
reddish; head, band on the prothorax, lobes of the thorax, one or two 
cross stripes on the abdomen, and a row of dots along each lateral 
margin of the abdomen dark brown or black, honey-tubes green; tail 
pale; legs green with dusky joints. The frontal tubercles and first 
joint of the antennae less prolonged than in the pupa or wingless in¬ 
dividuals. Length of the body about .07 of an inch; to the tips of 
the wings .15 inch. 
Winged male .—Size small, body short and narrow; head very broad 
and prominent in front; abdomen not broader than the thorax. Color 
wholly green, except the lobes of the thorax, which are olive. Length 
of body .05 inch; to the tips of the wings .11 inch. 
The Aphis mahaleb of Eonscolombe is but a variety of this species, 
and has the same injurious habits; it is described below. 
According to Dr. Fitch, this species had not been known in this 
country to an injurious extent until 1862, when it suddenly made its 
appearance in excessive numbers; and, as a consequence, the hops were 
injured to such an extent that they were rendered valueless in many 
yards, and in the best were deficient to the extent of from fifteen to 
