708 Pomona College Journal of Entomology 



average wing expanse of the speeies as taken here is slightly over 10 mm. All 

 measurements were made with a camera lucida. 



Antennal Articles — Antennal articles I, II, lY and V are given subequal, 

 wliile I have found that I and II are nearlj' equal and that IV and V are prac- 

 tically sub-equal, but that the articles IV and V are much longer than I and II 

 (nearly twice as long or a third longer). Articles III and VI correspond verj' 

 well. 



Rostrum — In the specimens taken here the rostrum rarely reaches beyond 

 the second coxie. Thomas reports it as reaching to the third coxeb. 



n'iiigs — The venation of the wings agrees very well in all respects except 

 the shape of the stigma. I have found it well rounded or nearly oblong instead 

 of angular. 



Though these differences are considerable, the general descriptions agree 

 well and I feel perfectly satisfied that the species is as named. No doubt that 

 with our earlv warm sjirings the young develop more lustily and this may account 

 for the difference in size, which may also influence other characters. 



Pemphigus populicaulis Fitch 

 (The Poplar-stem Gall-louse) 

 18.59 Fitch. Rept. Ent. N. Y. V, pp. 84.5-849. Original description. 

 1868 Walsh-Riley. Am. Ent. Ill, p. 57 and p. 245. Description and notes. 

 1873 Le Baron. Rept. Ent. 111. III. p. UK^. Notes. 



1879 Thomas. 8tli Rept. Ent. 111., j). 149. Description. 



1880 Henry. Am. Ent. I, p. 205. Reference to galls. 



1886 Oestlund. List Aphid. Minn., p. 55. Listed. 



1887 Oestlund. Aphid. Minn. p. 21. Description. 

 1890 Packard. Forest Insects, p. 434. Listed. 

 1892 Osborn. Cat. Hem. la.. )). I. SO. Listed. 

 1895 Cowen. Cat. Hem. Colo., p. 115. Listed. 

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



1903 Cook. Ohio Natural. IV, pp. 118-240. Bibliography. 



1903 Clarke. Li.st. Cal. Aphid., Can. Ent. XXXV, p. 134. Listed. 



1908 Vickary. Comp. Study of Ext. Anat. Plant Lice, pp. 4-5 and 15. 



Anatomy. 

 190s .Jackson. Syn. Gen. Pemphigus. Proc. Col. Hort. Soc. )))). 5 1- and 

 83-86. Description and notes. 



1909 Davidson. Aphid. In Vic. Stanford Univ.. Jr. Ke. Ent. vol. 11, p. 



299. Listed. 



1910 Davis. III. Ai)hid. .Ir. Kc. Kilt.. III. |). H 1. Listed. 

 1910 Williams. Aphid. Nebr., pp. !)-li>, DcscriiitioM and notes. 



191 1 Essig. Calif. Aphid. P. C. Jr. Ent. III. (). Kil. C.ilif. Hosts. 



wi.\(;En vivii'ARois kkmale (Figure 227 A) 

 Length of body 2 mm., width of thorax 0.6 nun., width of abdomen 0.75 mm., 

 wing expansion 6.7 mm. ]'rrr(iiling color — Nearly bl.-ick body .-ilmost or entirely 

 covered with a long whitish llcieeuli iier which gives the body .1 bluish tinge. The 



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