138 CHERRY. LEAVES — CHERRY APHIDIUS. 



stigma dusky, veins and outer margin of fore wings blackish. Length about 

 0.07. Hatched from an undescribed aphis infesting the base of the leaves of 

 the Balm of Gilead (Populus candicans). 



But without dwelling longer upon this interesting group of in- 

 sects which render us such important services, we close with a 

 notice of a species which destroys the aphis of the garden cherry, 

 and which differs from all the foregoing in its residence when in 

 the pupa state. As if fearful that the beak and feet of the dead 

 aphis would not hold its swollen body securely to the smooth 

 surface of the cherry leaf, the worm of this species when ready to 

 enter its pupa state perforates the abdomen of the aphis upon its 

 under side, probably as soon as its life is extinct, and spins a 

 cocoon for itself between the leaf and the body of the aphis, the 

 leaf forming the floor of the room for its residence, the abdomen 

 of the aphis forming its roof, and a gray paper-like membrane 

 which it weaves constituting the sides and attaching the body of 

 the aphis securely to the leaf. The walls of its domicil are so 

 thin that the inclosed pupa can sometimes be seen faintly through 

 them, of a bright yellow color. 



The CnERRT Aphidius (Trioxys Ccrasaphis^) is black, with its palpi or 

 feelers and legs pale yellowish brown ; antennge almost as long as the body, 

 18-jointed, the third and following joints equal, cylindric, thrice as long as 

 broad, the last elongated ovate; abdomen elliptic, rather narrower and short- 

 er than the thorax, scarcely pedicelled at its base, shining, tinged with brown- 

 ish; wings pellucid, stigma smoky white. Length 0.07. 



