82 PROCEEDINGS OF THE NATIONAL MUSEUM. you. 62. 
scales, the basal segmental bands widely triangular, separated from 
the lateral spots; white scales apically on the terminal segments; ven- 
ter whitish, legs black, with pale scales intermixed; femora and 
tibiae pale below; tarsi with white rings at the bases of the joints, 
rather broad on the hind pair. Wing scales rather broadly ovate, 
black, with many white ones rather evenly intermixed. 
The larvae inhabit salt marshes, in pools and narrow channels that 
are filled by the higher monthly tides. The adults frequent bushes 
in ravines near the shore. The species is extremely local and with 
very limited distribution. The marshes where it can breed are very 
few, and easily reclaimed, so that the species seems doomed with the 
advance of civilization. In certain localities the species has been 
occasionally numerous and troublesome. 
Distribution.—Coast of California between San Francisco and San 
Diego, where marshes are formed at the outlets of rivers. 
United States Records. 
CALIFORNIA: Oakland, August 26, 1903 (I. McCracken). 
Stanford University (V. L. Kellogg). 
‘San Lorenzo, June 28, 1901 (G. Hisen). 
Nordhoff, May 31, 1904 (A. D. Hopkins). 
Hueneme, Ventura County, May 28, 1918 (I. M. Jones). 
Laguna Beach (C. S. Baker). 
San Diego, March 9, 1906 (J. M. French). 
National City, June 19, 1906 (Dyar and Caudell). 
Group THIBAULTI. 
AEDES (HETERONYCHA) THIBAULTI Dyar and Knab. 
Aédes thibaulti Dyar and KwNaAs, Proc. Ent. Soc. Wash., vol. 11, p. 174, 1910. 
A rather large blackish mosquito. Mesonotum grayish yellow on 
the sides, a moderately wide median dark brown band, which widens 
squarely posteriorly by fusion with the posterior’side stripes. The 
marking is distinct and contrasted. Abdomen black above, with basal 
segmental triangular lateral white spots; venter whitish, with traces 
of black apical segmental bands, especially on the sides of the venter. 
Legs black, the femora white below; knee spots white. Wing scales 
all black, narrow. 
The habits and life history are unknown, the species being so rare 
that they have not come under observation. 
Distribution —Gulf States. 
United States Records. 
ARKANSAS: Scott, April 27, 1909 (J. K. Thibault). 
Cummins, May 8, 1915 (J. A. Le Prince). 
Brinkley, May 8, 1915 (J. A. Le Prince). 
Stuttgart, April 28, 1915 (J. A. Le Prince). 
Louts1ana: Mound, May 15, 1915 (D. L. Van Dine). 
Missourr: Cypress Swamp, Mississippi County, June 15, 1918 (LL. Haseman). 
