A SYNOPSIS OF THE APHIDIDAE 145 



cup to ash. There may be a migration to poplar as well, for the 

 .author has specimens that seem to be this species taken by Davidson 

 on poplar. Gillette 31 places this species as a synonym of T. populi- 

 conduplifolius Cowen, which attacks both Ranunculus and Populus 

 in Colorado. Davidson, however, is convinced that they are distinct. 



168. Thecabius populiconduplifolius (Cowen) 



Cowen, Colo. Agr. Exp. Sta., Bull. 31, p. 115, 1895. Pemphigus (orig. 



desc.). 



Davidson, Jour. Econ. Ent., vol. 3, p. 374, 1910. Pemphigus (list). 

 Essig, Pom. Jour. Ent., vol. 4, p. 699, 1912. Pemphigus (list). 

 Gillette, Annals Ent. Soc. Am., vol. 7, p. 61, 1914 (desc. and life history). 



Record. Populus trichocarpa; Stanford University (Davidson). 



This species was reported by Davidson on poplar at Stanford 

 University. Since then no further records of its occurrence in the 

 state have been made. In Colorado, Gillette finds that the common 

 buttercup, Ranunculus sp., is an alternate host and so considers the 

 preceding species as a synonym. This may be possible, but it is quite 

 doubtful. 



169. Thecabius populimonilis (Riley) 



Eiley, U. S. Geol. Surv., Bull. 5, p. 13, 1879. Pemphigus (orig. dese.). 

 Davidson, Jour. Econ. Ent., vol. 3, p. 374, 1910. Pemphigus (list) 

 Davidson, Pom. Jour. Ent., vol. 3, p. 398, 1911. Pemphigus (list). 

 Essig, Pom. Jour. Ent., vol. 4, p. 699, 1912. Pemphigus (list). 

 Gillette, Ann. Ent. Soc. Am., vol. 6, p. 485, 1913 (desc. and life history). 



Records. Populus spp. ; Tulare and Placer counties (Davidson); Santa Paula 

 (Essig), Eiverside, 1916-1917. 



Throughout central and southern California this species is found 

 on various species of Populus where it forms more or less globular 

 galls on the upper side of the leaves near the margins. In the vicinity 

 of Riverside the young stem mothers began to appear in April (1917). 

 When first observed in September, 1916, nearly all the galls were 

 empty while a few contained alate migrants (sexupara probably). 

 According to Gillette the eggs are laid on the trunks of Populus, thus 

 the entire life cycle is passed on the one host plant. This is rather 

 unusual for the Pemphiginae of this section. 



si Gillette, C. P., Some Pemphiginae attacking species of Populus in Colorado, 

 Ann. Ent. Soc. Am., vol. 7, pp. 61-65, 1914. 



