841 
No. 145. | 
Opulus, var. Americanum). These stems are often covered with 
lice, and the aphidius discovering them passes from one indivi¬ 
dual to another, dropping an egg into the body of each. The 
whole colony is thus destroyed by this parasite alone, the dead 
swoolen bodies of its victims remaining upon the stems crowded 
together as closely as they can stow themselves. I name this 
species 
The Cranberry ArniDius (Praon Viburnaphis). It is black and shining, with 
the short abdominal pedicel and the anterior legs wax yellow, their feet blackish at 
the tip, the hind knees yellowish; antennaj 15-jointed, the basal joint wider than 
long, the second nearly globular and slightly thicker than the following ones, the last 
not larger than the one preceding it; wings hyaline, reins outer margin and stigma 
black and shining. Length 0.076, wings expand 0.15. 
In the following species the veins are few'er in the fore wings 
and do not form any closed cells in the disk; there is merely a 
short robust curved vein from the inner angle of the stigma di¬ 
rected towards the apex and ending abruptly, and a vein running 
obliquely from the mid-vein to the outer margin forward of the 
stigma. These pertain to the genus Trioxys. 
The latter part of June the present year the willows in this 
vicinity were overrun, and many trees were almost defoliated by 
an undescribed species of aphis. But in a short time these in¬ 
sects w r ere all destroyed by their enemies, and the under surface 
of the leaves were thickly covered with the swoolen gray bodies 
of.those which had been killed by parasites. These yielded the 
following species: 
The Willow Aphidius (Trioxys Salicaphis). This is black and shining, with a 
long elliptical abdomen, of a honey-yellow color at its base gradually passing to black 
on its posterior part; legs honey yellow, tips of the feet and of the shanks and some¬ 
times the outer sides of the thighs dusky; feelers honey yellow; antenna! black, 
two-thirds as long as the body, 13-jointed, the third and following joints nearly 
equal, cylindrical, thrice as long as wide; stigma dusky. Length with the abdomen 
in its usual arched posture 0 06. 
The Poplar Aphidius (Trioxys Populaphis ) is black and polished, the abdomen 
long elliptical and much narrower than the thorax, the basal sutures sulphur yellow; 
legs sulphur yellow, the hind thighs black; antennae nearly as long as the body, 
15-jointed, third and following joints about equal, cylindrical, the last joint rather 
longer and thicker, oval with its apex rounded; stigma dusky, veins and outer mar- 
