40 SOUTHERN CALIFORNIA ACADEMY OF SCIENCES. 

 A New Plarvt-Louse from Southern California. 



BY T. D. A. COCKERELL. 



Aphis tetrapteralis, n. sp. Length of body about 1230 

 micromills, of wing about 2130 micromills: wings hyaline, stig- 

 ma 5^ellowish; head and thorax dark grey; abdomen sage green, 

 with very faint lateral spots; legs very pale yellowish, tarsus and 

 apex of tibia blackish; antennae short, blackish. Nectaries cyl- 

 indrical, short, about 60 micromills long and 30 wide; style prom- 

 inent, about as long as nectaries; hind tibia about 630, hind tar- 

 sus about 100 micromills; a very small tubercule at base of an- 

 tennse in front; antennae with the apical half of joint three 

 conspiciously darkened, with six large sensoria, arranged more or 

 less in three pairs; one sensorium at apex of fifth joint: length of 

 antennal segments in micromills: (i) 36; (2) 36; (3) 198; (4) 

 135; (5) 138; (6a) 95; (6b) 63. 



The apterous forms are bluish-green or greyish, about the 

 color of the food plant, but a little brighter. Mounted specimens 

 appear greenish-j-ellow. 



Hab. La Jolla, California, Aug. 9, 1901, very abundant on 

 Atriplex canescens tetraptera (Obione tetraptera, Benth. Bot. Sulph., 

 p. 48.) The aphis does not distort the plant, but it is followed 

 by a black fungus. There were some galls of AspJiondylia atrip- 

 licis (Townsend) — new to California — on the same plant; and 

 the butterfly Lycaena exilis (the larva of which feeds on the Atrip- 

 lex) was flj^ing around. 



Aphis tetrapteralis differs from A. atriplicis, by its smaller 

 size, mode of life and much shorter nectaries. It seems to be 

 related to A. monardae, Oestlund. 



Note on the Ant WKicK Attends Aphis Tetrapteralis. 



The original specimens of Aphis tetrapteralis at La Jolla were 

 attended by a small ant of the genus Cremastogaster. I collected 

 a couple of these and sent them to Prof. W. M. Wheeler, who 

 reports as follows: 



"The Cremastogaster ii!. either a new variety of C. lineolata 

 near coarctata, Mayr, or an entirely new species. The sculpture 

 is very peculiar, especially on the nodes and abdomen. In cer- 

 tain respects it agrees with C. vermiculata, Emery, a form de- 

 scribed from very few specimens. Am extremely sorry that you 



