THE MONTHLY BULLETIN. 



53 



THE WOOLLY BUTTERCUP LOUSE. 



Pemphigus calif ornicus Davidson. 

 (Fig. 42.) 



General Appearance.— Light green or yellow, covered with long 

 white floccnlence. The winged forms have dark head and thorax. 

 Quite a large form being 3.3 mm. in length. 



Life History.— Appears early in April on the lower leaves and at 

 the bases of the stems of the common buttercup. Both apterous and 

 winged forms are abimdant. Completely disappears in the fall. It 

 must have some alternate host which is still unknown. 



Distribution. — Throughout the central and southern part of the 

 State. Collected by Wm. Davidson at Palo Alto in Santa Clara 

 •County, and by the writer at Nordhoff in Ventura County. 



Food Plant. — The common California buttercup {Ranunculus cali- 



fornicus) . 



THE BEET LOUSE. 

 Pemphigus hetce Doaae. 



General Appearance. — The adult wingless lice are about one eighth 

 of an inch long; somewhat rounded or elongated in shape; whitish or 

 pale yellow in color with a large tuft of white floccnlence covering the 

 posterior end of the body. The legs, antenna?, and spots on the top of 

 the head are brown. The winged lice are a little larger, more elon- 

 gated and much darker in color. The head, antennge, legs and thorax 

 are black and being usually covered with a fine, white powder appear 

 bluish-black; abdomen dark green. The presence of this pest is easily 

 told by the white floccnlence which covers the lice as well as surround- 

 ing infested areas on the roots. 



Distribution.— Appears to be distributed only in the sugar beet 

 growing sections of the central and southern parts of the State. 



Food Plants.— As this is a subterranean aphid, only the roots are 

 affected, but often in such a way as to ruin portions of the crop. 

 Sugar beets are the only economic plants attacked to any injurious 

 degree. Wild yarrow, dock, knotweed {Polygonum aviculare) are also 

 attacked. 



THE POPLAR-STEM GALL-LOUSE. 



Pemphigus popidicaulis Fitch. 

 (Figs. 43, 44.) 



General Appearance. — Stem mother is slightly green or yellow, 

 covered with distinct rows of small cottony patches, one eighth to one 

 fourth of an inch long, and nearly as wide. Winged females are much 

 smaller, dark in color and covered with fine wax and long white 

 floccnlence. 



