A SYNOPSIS OF THE APH1DIDAE 107 



and Aphis euonomi Fabr. is in the length of the cornicles, which are 

 very much longer in this species. Measurements of specimens of the 

 alates from Oakland, Walnut Creek, San Jose, and Riverside are 

 herewith given: 



Measurements: Body length, 1.411 to 1.768 mm. (av. 1.621 mm.) ; 

 width of thorax, 0.714 to 0.782 mm. (av. 0.748 mm.) ; antennae total, 

 1.411 to 1.549 mm. (av. 1.499 mm.) ; III, 0.323 to 0.391 mm. (av. 0.365 

 mm.) ; IV, 0.272 to 0.323 mm. (av. 0.2914 mm.) ; V, 0.221 to 0.272 mm. 

 (av. 0.2518 mm.) ; VI, base 0.119 to 0.136 mm. (av. 0.311 mm.) ; VI, 

 spur 0.306 to 0.34 mm. (av. 0.323 mm.) ; cauda, 0.136 mm.; cornicle, 

 0.306 to 0.34 mm. (av. 0.3252 mm.) ; third tarsus, 0.119 to 0.136 mm. 

 (av. 0.1237 mm.). 



It will be seen that the cornicles are considerably more than twice 

 as long as the hind tarsi, in some cases practically three times, while 

 in A. euonomi Fabr., they are scarcely twice as long as the hind tarsi. 

 In A. euonomi Fabr. the hind tarsi are longer than the base of VI, 

 while the cornicles are shorter than VI spur. In A. hedera-e Kalt. VI 

 spur and the cornicles are subequal or on the average the cornicles are 

 very slightly longer, while VI base and the hind tarsi are also sub- 

 equal, the tarsi being shorter on the average. The secondary sensoria 

 in A. hedcrae Kalt. are small, irregular in size, and are scattered more 

 or less irregularly along III but in a fairly even row along IV and V. 

 They appear very much the same as in A. euonomi Fabr. There are 

 from thirteen to twenty on III, seventeen being the average; from 

 five to nine on IV, seven and eight being the usual number; and 

 usually one on V, although in a few cases there appear to be none. 



125. Aphis heraclei Co wen 



Cowen, Hemip. Colo., p. 120, 1895 (orig. dese.). 



Essig, Univ. Calif. Publ. Entom., vol. 1, p. 339, 1917 (list). 



Record. Heracleum montezzamum ; Berkeley (Essig). 



Recently Essig reported having taken this species on Heracleum 

 in Berkeley. The author has specimens from Essig, although he has 

 never collected it himself. This is the only report of the species since 

 Cowen 's original report and description. 



126. Aphis houghtonensis Troop? 



Troop, Ent. News, vol. 17, p. 59, 1906 (orig. desc.). 

 Davidson, Jour. Econ. Ent., vol. 7, p. 132, 1914 (list). 



Eecord. Ribes sanguineum; Contra Costa County (Davidson). 



