SYNOPSIS OF NORTH AMERICAN SYRPHID^. 2o9 



Senogaster Comstocki. (Plate XI, tigs. 1, la, lb.) 



Senof/asUr Comnlockl WillivStou, Proe. Am. Phil. Soc, xx, 326. 



Habitat. — New York ! 



$ . Length, 12'"™ ; of wing, 8"™. Face yellowish, blackish towards 

 the middle, and covered wich silvery white pubescence. Frontal tri- 

 angle blackish, whitish near the eyes. Antennae yellowish-red ; arista 

 yellow. Vertical triangle opaque black. Thorax black opaque, nearly 

 bare; dorsum with four conspicuous olive- gray stripes, nearly equi- 

 <listant, the lateral ones reaching from the yellowish humeri ; pleurae 

 reddish, dusted with whitish, especially on the meso and sterno jjleurse, 

 where it forms a conspicuous stripe; scutellum with a yellow margin. 

 Abdomen blackish-brown ; first segment as broad as the thorax, nearly 

 black, yellow on the sides ; second segment elongate, scarcely half as 

 wide behind, with two whitish elongate spots, not reaching the hind 

 margin; third segment of the same length, narrow, cylindrical, yellow 

 in front, narrowly above, broadly on the sides; fourth segment as long 

 as the preceding, expanded posteriorly, forming with the globular hypo- 

 pygium an ellipsoidal mass. Legs reddish-yellow, hind femora brown- 

 ish-black on the basal half; hind tarsi brownish. Wings nearly hya' 

 line. 



One specimen (Prof. J. H. Comstock). 



Macquart's description and figure of 8. coerulescens agree quite with 

 the present species, except that the conspicuous thoracic stripes are not 

 mentioned nor indicated. Was the specimen he described in good pres- 

 ervation? Bigot's Acrochordonodes vittatus (Bull. Soc. Ent. France, 131, 

 1878, female) applies very well indeed. Is it possible that they all per- 

 tain to one widespread species ? 



SYRITTA.* 



Syritta St. Fargeaii aud Serville, Eucycl. Meth., x, 808, 1825. 

 Copr ina ZetteTStedt, lus. Lapp., 584, 1840. 



Bather small, slender species, nearly bare, black, with yellow mark- 

 ings. Head hemispherical, not at all flattened, somewhat broader than 

 the thorax. Autennte short, third joint round; arista bare. Face 

 small, subcarinate, nearly straight, epistoma but slightly produced. 

 Eyes bare, very large, contiguous in the male. Thorax rather long, 

 scutellum thin on its edge, dark-colored. Abdomen slender, more con- 

 tracted in the male, abont twice as long as the thorax, and not wider. 

 Front and middle legs slender and small, the hind femora extraordi- 

 narily thickened, with short rigid spines below ; hind tibiae bent. Mar- 

 ginal cell of wing open ; third vein gently curved ; anterior cross-vein 

 near the middle of discal cell rectangular. Type of genus, S. pipiens 

 (Lina6). 



* 2vpiC,Eiv, to hum. 



