October, '10] DAVIS: ILLINOIS APHIDID.E 415 



Minn., No. 4 (1887), p. 37; Weed, Insect Life, Vol. 3 (1891), p. 287, 

 figs.; Davis, Ent. News, Vol. 21 (1910), p. 14, figs. Common 

 throughout the state and a pest of considerable importance on box 

 elder. First reported by Thomas. 



^Ch. populicola Thos.: Sanborn, Kans. Uni. Sci. Bull., Vol. 3 

 (1904), p. 36; figs. One of our most common species of Chaitophorus 

 in Illinois, occurring throughout the state. The several forms (winged 

 male with wings marked as are those of the viviparous female, and 

 oviparous female) are to be found on poplar twigs and leaves' in Sep- 

 tember. First reported by Thomas. 



*CA. quercicola Monl.: Bull. U. S. Geol. and Geog. Surv., No. 5 

 (1879), p. 32; Oestlund, 14th Ann. Kept. Geol. and Nat. Hist. Surv. 

 Minn. (1886), p. 49, (spinosus). I took the oviparous forms of this 

 species on the under surfaces of the leaves of post oak {Quercus ohtusi- 

 loba) at Kankakee, 111., Oct. 13, 1908, and have received winged and 

 wingless viviparous forms from Mr. W. P. Flint, who collected them 

 on white oak {Q. alba), at Heyworth, 111., April 10, 1908. The spec- 

 imens agree in every particular with the descriptions of Callipterus 

 guercifolii Thos. and Chait. spinosus Oestl., both of which species I 

 consider synonyms of Monell's quercicola. First reported by Monell. 



Winged viviparous female. — The following notes are offered to sup- 

 plement Monell's description.^ Antennae with 5-8 sensoria in a row 

 on III; from the alcoholic specimens the coloration appears as follows: 

 I, II, and III, dusky excepting a small pale area a little beyond the 

 center of III. IV and V, pale except the dusky tips, and VI entirely 

 dusky except basal half of base VI. Abdomen with a row of dusky 

 tubercular areas bearing spines on the dorsum, these being most con- 

 spicuous a't the anterior end; a similar row on each side. Plate 27, 

 figures 1 and 2. 



Wingless viviparous female. — The descriptions given by Monell ^ 

 and Oestlund ^ are quite characteristic for the species. 



The excellent description of the wingless oviparous female given by 

 Oestlund ^ agrees exceedingly well with my notes and specimens. 



*Ch. viminalis Monl.: Bull. U. S. Geol. and Geog. Surv., No. 5 

 (1879), p. 31; Weed, Psyche, Vol. 5 (1889), p. 133. Common in all 

 parts of the state on willow. It varies greatly in color, — from a light 



I Notes on the Aphididae of the United States, etc. Bull. U. S. Geol. and Geog. 

 Surv., Vol. V, No. 1, p. 32, 1879. 



^Loc. cit. 



'Synopsis of the Aphididae of Minn. Bull. 4, Geol. and Nat. Hist. Surv. Minn., 

 p. 38, 1887. 



* List of the Aphididae of Minn., etc. 14th Ann. Re.pt. Geol. and Nat. Hist. Surv. 

 Minn., p. 50, 1886. 



