ART. 9 AMERICAN XYLOTINE SYRPHID-FLIES SHANNON 41 



apiformis (genotype of Pocota European) shows the two to be con- 

 generic and honiboides is therefore retained in Pocota. The first 

 posterior cell in Pocota is closed at the wing margin; the legs are 

 simple and the hind femur slender. These characteristics combined 

 with the dense pubescence allies Pocota to certain of the Criorrhinini. 

 Hadroviyia is of a Xylotine character. 



POCOTA BOMBOIDES Hunter 



The venation and metasternum in this species differ from those in 

 all other Xylotini. The shape of the face is the same as in Xylota 

 and HadroTnyia^ but the venation and pubescence indicates a rela- 

 tionship to certain of the Criorrhinini, Anterior half of mesonotum 

 yellow pilose; posterior half black; scutellum intermixed black 

 and yelloAv pilose; abdomen chiefly black pilose; yellow on anterior 

 half of fourth and sometimes along lateral margins of abdomen; 

 fourth tergite blackish, dark green, aeneus on anterior half; metas- 

 ternum pubescent, greatly reduced, each sclerite being about the size 

 of metathoracic spiracle and longer than broad ; mid femora of male 

 simple; first posterior cell but little longer than broad, the apex acute 

 and very close to wing margins. The genitalia are strikingly differ- 

 ent from those of grandis. The basal lobe of the style in grandis is 

 small, swollen, and but little differentiated from the style; the style 

 acutely pointed. The basal lobe of the style of homboides is very 

 large, deeply sunken, saucerlike, and well differentiated from the 

 style; style obtusely pointed, spinose. 



Type locality. — Summit Sierra Nevada, California. Has also been 

 collected on summit of Mount Moscow, Idaho. The males are swift 

 fliers and love to poise in midair. 



Type. — In University of Nebraska. 



Genus HADROMYIA Williston 



Hadromijia Williston. 



Hadromyia, as synonym of Pocota, Williston. 



HADROMYIA GRANDIS (Williston) 



One of the largest of Syrphidae. Anterior half of mesonotum 

 yellow pilose, posterior half and anterior two-thirds of abdomen 

 black pilose; fourth tergite bright green-aeneous with yellow pile; 

 metasternum pubescent, of normal development; base of middle fe- 

 mora of male with long curved spine; first posterior cell twice as 

 long as Avide; apical cross vein joining third vein acutely, a distinct 

 petiole beyond the angle ; posterior cross vein twice as long as upper 

 outer section of discal cell (venation like that of Xylota in general 

 aspect). Length 20-23 mm. 



