LIST OF HOMOPTEROUS INSECTS. 949 



than the space between the tip of the second fork and that of 

 the fourth vein ; fourth vein rather long, slightly curved for half 

 its length, nearly straight from thence to the tip, which is much 

 nearer to the tip of the second fork than to the tip of the rib- vein. 



Var. Fern. — Fourth joint of the feelers little more than half 

 the length of the third ; fifth a little shorter than the fourth ; 

 sixth much shorter than the fifth ; seventh much longer than the 

 fifth. Sometimes the second fork of the third vein varies most in 

 the wings of one insect. 



Var. Male. — The fourth vein vanishing from the middle to 

 the tip. 



Var. Male. — The second fork of the third vein longer than the 

 space between the forks, and still more so than the part before 

 the first fork. 



a — z. England. (In Canada Balsam). From Mr. Walker's collec- 

 tion. 



20. Aphis hirticornis. 



Aphis hirticornis, Walk. Ann. Nat. Hist. Ser. 2, i. 447, 20. 



Kib-vein hardly approaching the fore border, and then very 

 slightly diverging from it ; the angle is very blunt, and hardly per- 

 ceptible, and its outward side is much shorter than the space be- 

 tween the tip of the rib- vein and that of the fourth vein ; first vein 

 very oblique to the rib-vein ; second vein more oblique than the 

 first, from which its distance at the base is almost or hardly one- 

 third of the distance at their tips ; third vein vanishing at its 

 source, almost parallel to the second till near the tip, their mu- 

 tual distance on the hind border a little exceeding that between 

 them along the rib-vein, the latter distance much more than that be- 

 tween the first and second veins, but on the hind border it is much 

 less ; distance between the two forks much longer than the third 

 vein before the first fork or than the second fork ; a nearly equal 

 distance between the tips of the third vein and of the first fork, be- 

 tween the tips of the second and third veins, and between the tips 

 of the first and second forks, which last distance much exceeds that 

 between the second fork and the tip of the fourth vein ; fourth vein 

 rather long, slightly curved for half its length, nearly straight 

 from thence to the tip, which is much nearer to the tip of the 

 second fork than to the tip of the rib- vein. 



3o3 



