STATE HORTICULTURAL SOCIETY. 169 



The wing characters are as follows : Distance between the first and 

 second discoidal veins, at the base much less than half that between them 

 at the tips ; third a little farther from the second at the tip than at the 

 base, and as far from the second at the base as the second is from the 

 first; the first veinlet (fork vein) very much nearer to the second at the 

 tip than it is to the third vein. 



36. Aphis polygonii^?'). The Knot-weed Plant-louse. 



Is found on the Spotted Knot-weed {^Polygonum persicaria). There 

 are two species found on the knot-weed in England, the Aphis polygotiiy 

 Walk., and the Aphalara polygoni, Forst. ; whether this is identical with 

 either, I am unable to say. 



37. Aphis viburni i^?'), Fabr. The Cranberry Plant-louse. 



Found on the fruit stems of the High Cranberry {Viburnum opulus, 

 var. Americanutti). It is possible this may be a different species from that 

 named by Fabricius, which he says infests the leaves as well as the stems. 

 The veining of the fore wings of Fabricius' species is as follows: 



The distance between the first and second discoidal veins at the tips 

 more than twice that between them at the base ; third a little nearer the 

 second, at the base, than the second is from the first fork (or veinlet). 



38. Aphis candicans{f). ■ The Balm of Gilead Plant-louse. 



Infests the base of the leaves of the Balm of Gilead, and appears to^ 

 be different from the A. populi of Linngeus. But in order that this may 

 be determined, I give here briefly the characters of the latter, which has 

 been transferred by Koch to his genus Chaitophorus . 



The rib-vein hardly approaching the front border and then very 

 slightly diverging from it ; its angle very blunt and scarcely perceptible ; 

 the first discoidal vein very oblique to the rib-vein, from its source to the 

 base of the wing is less than three-fourths the distance from its tip to the 

 base of the wing ; second vein more oblique than the first, more than 

 three times as far from the first at the tips as at the base; the third vein 

 obsolete at the base. 



The position of the rib-vein, the obliquity of the discoidal veins, and 

 the obsoleteness of the third at the base, together with a slight difference 

 in habits, are doubtless the reasons why this has been removed to another 

 genus. 



39. Aphis berberidis, Kalt. The Barberry Aphis. 



Found on the under side of the leaves of the Barberry. Black ; the 

 breast and abdomen pale yellow, tip black : legs dusky. Larva and pupa 

 pale, with a green or black stripe on each side of the back parallel with 

 the outer margin. Length, o. lo inch. Our species is probably identical 

 with that found in Europe. 



