2 
of great loss in the principal pea-growing regions of this country, espec- 
ially where peas are grown for canning. It was, in fact, one of the 
most important of all insects that ravaged crops in the United States 
during the seasons of 1899 and 1900, and there appears to be little 
prospect, unless the unforeseen happens, of any decrease in its devasta- 
tions. On the contrary, it is to be expected that it will widen its range, 
as it has apparently already done to some extent. 
DESCRIPTIVE. 
The pea aphis is one of unusual size among those found infesting 
gardens, and the largest of the green species which attack the pea and 
related plants. The length of the body of winged, viviparous females 
is about 75 inch (4.5 ™™.), and the total wing expanse about is inch 
(9 to 11 ™™.). The general color of both the winged and apterous or 
wingless forms is uniform pea-green, the same color as the insect’s 
favorite food plant. The eyes are prominent and reddish brown in 
color. The antenne are lighter than the body and the tubercles promi- 
nent; the joints are darker than the rest of the segments, the seventh 
joint filiform and fuscous. The legs are long and conspicuous; tarsi, 
distal ends of tibie, and femora fuscous. The nectaries are fuscous at 
the tips, otherwise of the same color as the body. 
A typical female of this insect is shown in figure 1 with wings 
expanded, showing venation at a, and a lateral view of the same with 
wings folded in their natural position when the insect is at rest or feed- 
ing is presented at b. At © an apterous or wingless form of the insect 
is shown, and d illustrates the nymph in its last stage. The structure 
of the third antennal joint of the winged form may be seen at e, highly 
magnified. 
DISTRIBUTION. 
There are good reasons for believing that this aphis was introduced 
from abroad, probably from Europe, one being that injury of the 
severity noted by a species of insect hitherto unrecognized as distinct 
from others of its kind is almost without a parallel in the history: of 
economic entomology. It seems probable, therefore, that we have in 
the pea aphis a case analogous to that of the European gipsy moth, 
which was present in this country for about twenty-five years before it 
became a pest. 
The first notice of severe attack to pea that can with positiveness be 
attributed to the pea aphis was reported to this office, in a letter dated 
May 16, 1899, by Mr. Thomas Bridges, Bridges, Va. This was followed 
within the next few days by reports from Virginia and Maryland, and 
soon afterward injury was recognized in other States and in Canada. 
During the previous season (1898), however, this pest was present in 
AG-—49 
