October, ’20] 
WADLEY: SQUASH BUG 
417 
work on which this article is based was done by the writer while in the 
service of the Federal Bureau of Entomology at Wichita, Kans., 
late in 1916 and in 1917 and 1918; and at Muscatine, Iowa, in 1919. 1 
Importance 
\ 
Both adults and young, especially the latter, injure the plant by 
sucking its juices, and probably also by the toxic effects of their bites. 
Small brown spots mark the feeding places of nymphs on the leaves. 
Further feeding causes large leaf areas to assume a grayish discolora¬ 
tion and die. If the bugs are abundant enough, the whole plant wilts 
rather suddenly after the death of several leaves. Young seedlings 
succumb very quickly to squash bug attacks, but since the bugs are 
scarce early in the season this injury is slight. It is in late summer, 
when the weather is hot and dry, and squash bug nymphs numerous, 
that the worst injury occurs. After the vines are killed, bugs are found 
clustered on squash or pumpkin fruits sucking their juices. If its 
normal food plants are overcrowded or exhausted, the squash bug may 
attack other nearby cucurbits, but it is a serious enemy only to squashes 
and pumpkins. The quick growing summer squashes are especially 
favored. 
Description 
The adult is dark brown in general coloration. This effect is given 
by a yellow ground color, more or less densely dotted with black punc¬ 
tures; variations in density of punctures result in mottling. The 
antennae, and the membrane of the wing, are solid black. The dorsal 
surface of the abdomen covered by the wings, is crimson. Adults vary 
in length from 13 to 16J mm. and in width from to 6 mm., averag¬ 
ing 15 and 5 mm. respectively. The female is slightly larger than the 
male. The newly hatched nymph has a bright green body with red 
head, thorax and appendages; but within an hour or so the red has 
changed to black and the green has deepened. These colors remain 
during the first instar, after which the nymphs are usually gray with 
black head and appendages. For a short time after each molt, the 
bug is green with red head and appendages. The nymph has an ab¬ 
domen large in proportion to the rest of the body, giving a pear-shaped 
appearance. The wing pads are conspicuous in the later instars. Both 
nymphs and adults are characterized by a strong sickening odor, 
common among Heteroptera. 
The egg is whitish when first deposited but soon becomes a metallic 
shining brown. It is about lj mm. in length and a modified oval in 
1 During 1918 some of the work was done, under the writer’s direction, by Mr. 
F. M. Liggett. Some of the data on hibernation were taken from the notes of the 
late Mr. H. O. Marsh. 
