SYNOPSIS OF NORTH AMERICAN SYRPHID^. XXV 



bb. Hiud femora more or less thickened, with spines or bristles below, never with 



a bitid spine near the tip. 

 c. Hind femora very much thickened, anterior cross-vein rectangular. 



Syeitta St. F. & Serv. 



cc. Hind femora never remarkably thickened, hind coxae often with spinous process; 



cross-vein always oblique Xylota Meig. 



CriorUnini.—'Mostij large species, pilose. 

 o. Scutellum, margin of thorax, and pleurae witl^bristly hairs ; face distinctly tuber- 



culate ; femora slender Chrysochlamys Eond. 



aa. Thorax wholly without bristly hairs. 



b. Face short, not produced, concave, not tuberculate ; hind femora more or less 



thickened. 



c. Abdomen elongate. 



d. Abdomen shining or opaque black Bracuypalpus Macq. 



d(l. Abdomen with bright bronr.e cross-bands Calliprobola Rond. 



cc. Abdomen very broad, thorax densely pilose, large species, 



PocoTA St. Farg. & Serv. 

 bh. Face produced, longer than. the front. 



e. Face produced forward, pointed, concave from the antennae to the tip, not tuber- 



cuhite, subcarinate; hiud femora thickened Criopkora 0. S. 



ee. Face not evenly concave, tuberculate. 

 /. Third joint of antennae produced above into a conical process, terminating in the 



thickened arista ; femora slender Merapioidus Bigot. 



//. Third joint of antennte transversely oval, but little broader than long; femora 



rarely thickened Criorhina Macq. 



Tro2ndia, Senogaster, Syritta, SLiid Xylota form a natural, slightly diver- 

 gent group, showing an unquestionable relationship on the one hand 

 with Mallota, on the other with Brachypalpus. 



The relationship of Brachypalpus with Pocota and Calliprobola is evi- 

 dent, and between these and CriorJdna, Crioprora forms a natural con- 

 nection. Merapioidus and Chrysochlamys are less intimately related. 



MILESIJ^^I. 



Large species, thinly pilose or nearly hare, with yellow spots or stripes on 

 the thorax above, the abdomen conspicuously yellow banded. Anterior cross- 

 vein beyond the middle of the discal cell, oblique; third longitudinal vein 

 gently curved {except in Milesia). Antennal arista bare; hind femora 

 elongated and moderately thicJcened. 



a. Hind femora with a conical protuberance below, near the end. 



Ik Mai'giual cell of wing closed ; antennae short Milksia Fabr. 



hi). Marginal cell open, antennae more or less elongate Spilomyia Meig. 



aa. Hind femora without such protuberance; marginal c(,'ll open. 



c. Antennae inserted high up, on a conical projection; front short, face much pro- 

 duced downward Sphecomyia Latr. 



cc. Antennae situated low down, short; face not longer than the front .. Temnosto ma. 



Spilomyia and Temnostoma are closely allied, as is also Sphecomyia. 

 Milesia, in the structure of the face and wings, is more remote, but the 

 legs and general habitus show an incontestable relationshij). 



