38 Thomas Albert Williams 



Winged form: Antennae shorter than the body, on inconspicuous tuber- 

 cles, black; VII longer than III. Head and thorax black. Neck and pro- 

 thorax reddish. Wings rather heavy and large, with yellowish insertions. 

 Abdomen, honey tubes and tail as in apterous form except that the honey 

 tubes and tail are slenderer. Legs all black. Beak reaching beyond second 

 pair of coxae, black tipped and very acute. The abdomen is very large in 

 both forms ; sometimes almost spherical, giving the insects a broadly 

 pear-shaped outline. Length of body 2.83 mm. 



A very large aphis, moving quickly when disturbed, with a 

 jerky motion. In size and general appearance it is* very like a 

 Siphonophora; but the generical characters are undoubtedly those 

 of Aphis. 



On Artemisia carta, generally on the upper leaves and ends of 

 branches. Squaw Canyon, June 24, 1890. 



Cotypes in collection of the University of Nebraska (no. 53) 

 and of the U. S. National Museum (no. 56). 



44. Aphis atriplicis Linnaeus. 



Linnaeus, Fn. Sv., p. 1000 (1761). 



Schrank, Fn. Boi., II, 109, 1196 (1801). Aphis chenopodii. 



Kaltenbach, Mon. Pflan., p. 107 (1843). 



Buckton, Mon. Brit. Aph., II, p. 87, pi. LXV, figs. 4-7 (1879). A. 

 atriplicis. 

 Apterous viviparous female: Green, more or less pulverulent, elliptical. 

 Antennae pale, with dusky tips, hardly half the body in length. Eyes dark 

 red. Legs short, pale, with slightly dusky tarsi. Honey tubes very slen- 

 der, subclavate, slightly dusky, especially at the tips, hardly as long as the 

 conspicuous, upcurved, concolorous tail. 



J ringed viviparous female: Somewhat larger than apterous female, 

 ovate. Head and thorax black. Eyes dark reddish brown. Antennae 

 hardly two thirds the body in length, black, with pale base, xninutely annu- 

 late ; III longest, with a single row of large sensoria. Beak short, not 

 reaching the middle coxae. Prothorax brownish, without lateral tubercles. 

 Wings with yellowish insertions and subcostal and robust, smoky black 

 oblique veins. Stigma dusky, rather long, but very obtuse. Legs dusky to 

 blackish. Honey tubes as in apterous female, but more dusky. Tail more 

 slender and acute. Abdomen green, with brown marginal spots and trans- 

 verse bands, these latter often more or less obsolete. Length of body 1.60 

 mm., to tip of wings 3 mm. 



Very common on pigweed (Chenopodium sp.) in June and 

 July, and sometimes on dock (Rumex sp.). The lice cluster 



122 



