CHERRY. LEAVES — APHIDIUS SPECIES. 137 



Opulus, var. Jimericanum). 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 

 swollen bodies of its victims remaining upon the stems crowded 

 together as closely as they can stow themselves. I name this 

 species. 



The Cranberry Apttmirrs (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; antennae 15-jointcd, 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, 

 veins outer margin and stigma black and shining. Length 0.075, wings expand 

 0.15. 



In the following species the veins are fewer 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 Avere overrun, and many trees were almost defoliated by 

 an undescribed species of aphis. But in a short time these in- 

 sects were all destroyed by their enemies, and the under surface 

 of the leaves were thickly covered with the swollen gray bodies 

 of those which had been killed by parasites. These yielded the 

 following species : 



The Willow Apiudius (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 sometimes the outer sides of the thighs dusky; feelers honey- 

 yellow; antennae 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, 0.0G. 



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, cylin- 

 drical, the last joint rather longer and thicker, oval with its apex rounded; 



