144 MISCELLANEOUS STUDIES 



University, but later wrote the author that he was mistaken in his 

 determination, the species being P. populicaulis Fitch instead. 



Just recently the author received specimens of the sexupara of this 

 species from J. R. Parker, Bozeman, Montana. These were taken by 

 S. H. Jones in Port Allen, Louisiana, in September, 1915, on the roots 

 of cabbages. Jones notes that cabbage and other cruciferous plants 

 are the alternate host of this species. This spring the author received 

 a large number of apterae of a species of Pemphigus taken in Orange 

 County on the roots of cabbage. A specific determination of the 

 species was impossible but it may have been this one. 



40. Genus Thecabius Koch 

 Koch, Die Pflanzenlause, p. 294, 1857. Type Pemphigus affinis Kalt. 



This genus is very similar to Prociphilus, and by some authors, 

 particularly Baker, 30 is considered as synonymous. However, for 

 present purposes the author proposes to retain it for the three species 

 included herewith. 



KEY TO CALIFOBNIAN SPECIES 



1. Antennae short, barely reaching to the metathorax, and not one-third as long 



as the body. Ill but slightly longer than VI populi-monilis Eiley 



Antennae longer, reaching beyond the base of the abdomen, and about one-half 



as long as the body. Ill considerably longer than VI 2 



2. V and VI with secondary seusoria populi-conduplifolius Cowen 



VI without secondary sensoria californicus Davidson 



167. Thecabius californicus (Davidson) 



Davidson, Jour. Econ. Ent., vol. 3, p. 372, 1910. Pemphigus ranunculi n.sp. 

 (orig. desc.). 



Davidson, Jour. Econ. Ent., vol. 4, p. 414, 1911, renamed Pemphigus cali- 

 fornicus Dvdn. 



Essig, Pom. Jour. Ent., vol. 4, p. 699, 1912. Pemphigus (desc. ala. and 

 apt. female). 



Davidson, Jour. Econ. Ent., vol. 7, p. 127, 1914 (note). 



Records. Ranunculus californicus; San Francisco Bay region (Davidson, Mor- 

 rison, Essig, author): ? Populus sp. ; Walnut Creek, Contra Costa County, May, 

 1915 (Davidson) : Fraxinus oregona; Walnut Creek (Davidson). 



This aphid is found quite abundantly on the roots and stems of 

 the small California buttercup in the San Francisco Bay region. 

 According to Davidson there is a migration during April from butter- 



so Baker, A. C., Identity of Eriosome pyri, Jour. Agr. Ees., vol. 5, p. 1118, 



