6l2 CALIFORNIA ACADEMY OF SCIENCES. 



basal half or more. Face entirely greenish black. Wings 

 clear, stigma yellowish. Legs black, tibiae and tarsi more 

 or less yellowish, the anterior and middle pairs almost 

 wholly so. Scutellum with marginal bristles, abdomen 

 moderately hairy. 



35. Syrphus opinator O. Sack. California. One 

 female. It agrees in all respects wath Osten Sacken's 

 description of the females w^hich he referred to this spe- 

 cies (as quoted b}^ Williston in Monogr.) The metallic 

 green portion of the front is dusted with brassy yellow 

 pollen only posteriorly and laterall}', leaving a dark shin- 

 ing crescent on the front border, concave anteriorly. 

 Length, 10 mm. 



36. Voluceli>a estebana n. sp. 



San Esteban, Baja California, Mexico (Cal. Acad. 

 Sci.). April, 1889. A pair, 6 ? , i>i coita. Length, 75^ 

 mm. 



Small, light colored except head and thorax. Face 

 and front pale whitish yellow, median vitta of face well 

 defined and rather narrow, with stripe of cheeks black or 

 dark brown. Front of female black across ocelli, near 

 antennas with two brown spots. The two browai spots 

 become, in the frontal triangle, a margin along the eyes. 

 Face and eyes w^hitish pilose, frontal triangle blackish 

 pilose, also front of female above. Antenna^ brown, ba- 

 sal joints yellowish or lighter; arista longer than third 

 joint, blackish, densely short plumose above. Thorax 

 shining black, with tw^o median whitish pollinose vittas 

 abbreviated behind; sides, scutellum, and two longitudi- 

 nally elongate spots in front of latter, pale yellowish or 

 whitish. Pile of thorax and scutellum whitish, that of 

 pleura longer. Abdomen brownish, the second and third 

 segments broadly pale yellowish or w^iitish, the light col- 



