300 CALIFORNIA ACADEMY OF SCIENCES [Proc. 4th Ser. 



slender bristles to level of anterior ocellus ; parafacial at base 

 of antenna almost as wide as third antenna! joint, slightly 

 narrowed below ; cheek about three times as high as width of 

 parafacial, vibrissal angle produced; third antennal joint 

 rounded at apex; arista pubescent; presutural acrostichals 

 slender, long, two-rowed ; postsutural dorso-centrals four ; disc 

 of scutellum with numerous long hairs; lower posterior 

 sternopleural weak. Abdomen cylindrical, slightly tapered 

 posteriorly, fourth tergite and sternite the longest; hyix)py- 

 gium not exserted; fifth sternite almost transverse apically. 

 Fore tibia without median bristle ; mid-tibia with one or two 

 posterior bristles; hind femur rather abruptly thickened at 

 base ventrally, and distinctly thicker near base than at middle. 

 the antero-ventral surface with three bristles near apex ; hind 

 tibia with one median antero-dorsal bristle. Fourth vein with 

 but little indication of the forward curvature so distinct in 

 allied species. 



Female. — Similar in color to the male, but the thorax has 

 three brown vittae, the central one not extending o\er scu- 

 tellum. 



Profile as in male ; frons over one-third of the head-width ; 

 each orbit with six or seven bristles and a few lateral hairs. 

 Apical genital segment with numerous stiff, short bristles 

 below. Tibial bristles as in male but there is very often an 

 antero-ventral bristle on hind tibia. 



Length, 5-6 mm. 



Type, male, No. 525, C. A. S., Huntington Lake, Calif., 

 altitude 7000 feet, July 28, 1919; Mrs. E. P. Van Duzee. coll., 

 and allotype, female. No. 526, C. A. S., also one male and 

 one female paratype, topotypical, all from same locality. There 

 are also three males, paratypes, taken July 16, 17 and 22, 1919, 

 at same place by E. P. Van Duzee, and one female taken July 

 29, 1919, by E. P. Van Duzee at Cascada, Calif., alt. 5000 feet. 



A female taken at same place as type differs in being much 

 darker and in having two antero-dorsal bristles on hind tibia. 



From other species of Limnophora this species may readily 

 be distinguished by the peculiar shape of the hind femur. It 

 belongs to the group which has the ventral plate of prothorax 

 with setulose hairs along its margins and the third vein setu- 

 lose at base. 



