XXVI miLLETIN 31, UNITED STATES NATIONAL MUSEUM. 



The nearest relationship in the preceding group is evidently with 

 certain species of Criorhina. A resemblance between Milesia and Pier- 

 optila cannot be overlooked. 



Bather large, hare, elongate species ; antennce longer than the head, sec- 

 ond and third joints swollen, terminating in a style; anterior cross-vein 

 beyond the middle of the discal cell, nearly straight; third longitudinal vein 

 with a stump projecting into the first posterior cell. . . . Ceeia Fabr. 



This genus has been divided on the presence or absence of the frontal 

 process, but the character is insufficient. 



CHARACTERS OF THE FAMILY SYRPHID^E. 



A false longitudinal vein between the third and fourth longitudinal veins;* 

 fourth longitudinal vein united at its extremity with the third; basal cells 

 large ; face without subantennal grooves. 



Head hemispherical, often elongated or produced in the lower part, 

 as broad or a little broader than the thorax. Face moderately broad, 

 bare, or clothed with dust or short pile, excavated in profile under the 

 antenna} and projecting below, or with a distinct convexity near the 

 middle i)art : never with longitudinal furrows or lateral ridges, usually 

 convex transversely, sometimes with a median ridge. Oral opening 

 large ; proboscis rarely much elongated, usually but little projecting, 

 and, when at rest, concealed within the mouth; pali)i one jointed: 

 labrum-epipharynx, hypopharynx, maxillae and labium present. Front 

 never excavated, often swollen, sometimes with a more or less elongate 

 process which bears the antennae. Antennae usually porrect, approxi- 

 mate at their base, three-jointed ; the third joint more especially of varied 

 shape, usually flattened and with a dorsal bristle, either bare or plu- 

 mose; very rarely the third joint is not flattened, and is provided at 

 the tip with a thickened style. Eyes large, bare or pilose, in the male 

 usually contiguous between the base of the antenna) and ocelli. Ocelli 

 always present. Thorax comparatively large and robust, moderately 

 arched above ; scutellum large, usually convex, often translucent, rarely 

 with spines on its border. Tegulae of moderate size. Abdomen com- 

 posed of five or six visible segments, rarely with only four. Hypopy- 

 gium usually not prominent. Shape of the abdomen variable; slender, 

 linear, clubbed, short, oval, and all intermediate forms. Legs usually 

 weak, sometimes strong; the hind femora not infrequently moderately 

 or much thickened, the hind tibiae not rarely arcuated and compressed, 

 metatarsi rather long, cox* short ; the hind coxae, femora, and tibiai, 

 more especially in the male, in not a few species, armed with spurs, pro- 

 tuberances, or spines; the front and middle tibiie and tarsi rarely flat- 

 tened, or with structural variation. Macroch setae rarely present in any 

 ■* Sometimes al)sent in Chrysogaster, Volucella, etc. 



