704 Pomona College Journal of Entomology 



Pemphigus populimonilis Riley 

 (The Biad-likf tDttoinvuod Gall-louse) 

 1897 Bull. U. S. Gcol. Surv., V, ))]). 13-li. Original description. 

 1880 Thomas. 8th Rcpt. Ent. 111., p. 20r>. Notes and description. 

 *]880 Mcndeiihall. iMinn. State Hort. Soc. ,MSS. Li.sted. 

 1887 Oestlund. Aphid. Minn., !>. 24. Listed. 



1890 Packard. Forest Insects, p. K'Si. Listed. 



1891 Xiswander. Bull. No. 2, Wyoni. Agrcl. Exp. Sta. 

 1895 Cowen. Hem. Colo., p. 1I6. Listed. 



1901 Hunter. Apliid. N. A., p. 78. Bibliography. 



1908 Jackson. Syn. of Gen. Pemphigus, Colum. Hort. Soc, pp. 201-206. 



Description and notes. 



1909 Gillette. Plant Louse Notes, Jr. Ec. Ent.. V, p. 356. Listed. 



1910 Williams. A])liid. of Xebr., pp. 10-12. Descrii^tion and notes. 



1910 Davidson. Calif. Ai>hid.. Jr. Ec. Ent., Ill, p. 37L Listed. 



1911 Essig. Host Index to Cal. Aphid., P. C. Jr. Ent., Ill, p. tdl. Hosts 



in California. 



WINGED VIVIPAROUS FEMALE (Figure 22i A) 

 Length of body 3.3 mm., greatest width of the thorax 1.2 mm., greatest 

 width of the abdomen 1.6 mm., wing expansion lO.l mm. Large species. Pre- 

 vailing color — Body dark, covered with long white flocculence which gives it a 

 bluish-white color. The flocculence may be very short or be replaced by a fine 

 white powder, which always covers the ventral surface. Head — Black or dark 

 slate, dorsal surface usually naked, ventral surface covered with fine white powder, 

 very small and narrow, being less than half as wide as the mesothorax, evenly 

 rounded anteriorly and fitting tightly against the prothorax. Eyes — Very dark 

 reddish brown or black, large. Antennae — (Figure 221 B). Reaching to base 

 of the posterior wings or only to the base of the primary wings, black or very 

 dark brown throughout; articles III, IV and V somewliat clavate; lengths of 

 the articles: I, 0.07 mm.; II, 0.08 mm.; Ill, 0.21 mm.; IV, 0.1.5 mm.; V, 0.1 1 

 mm.; VI, 0.21 mm.; total 0.89 mm. The sensoria are large, transverse and situ- 

 ated as follows: III, six to nine; IV, three to five; V, one to four; VII one. 

 Rostrum — Reaches to or nearly to the second coxae, dark throughout, but darker 

 at tip. Prothorajc — Slightly wider than the head, but very short, black. Meso- 

 thorax — Black, lobes well developed and extending much higher than any other 

 part of the body. Meiathora.r — Black with muscle lobes well developed. Abdo- 

 men — Dark olive green to brown, covered with long white flocculence or fine 

 powder (always so ventrally), widest near the middle and somewhat pointed at 

 the posterior end, lateral margins of each segment with darker spot, which shows 

 after the body has been cleared for mounting. Legs — Normal, hairy, black or 

 very dark brown throughout. IVings — Sul)hyaline, large. Primary — Length -l-S 

 mm., width 1.6 mm. Costal vein heavy, dusky; subcostal wide, dusky; stigma 

 oval to oblong in shape, lower margin well-rounded, lower portion much darker 

 than remainder, with several rows of short hairs, all dusky ; length O.9O mm., 



