CHILOSA.— MELANOSTOMA. 



9 



Eab. Mexico, Ciudad in Durango 8100 feet (Forrer). 

 Two specimens. 



This species is distinguishable from C. petulca, Willist., by the absence of bristles 

 on the scutellum ; from C. baroni, Willist., by the red antennee and metallic coloration ; 

 from C. occidentalis, Willist., and C. hoodiensis, Bigot, by the light-coloured pile of the 

 mesonotum ; and from C. lasiophthalma, Willist., by the facial profile. 



3. Chilosia sororcula, sp. n., s . 



Eyes bare. Frontal triangle not swoUen, shining black, with an impressed line and black pile. Antenna? red ; 

 third joint rounded, not large ; arista pnbescent. Pace shining black, bare, save on the narrow orbits ; 

 whitish-poUinose, very thinly below, more thickly near the antennae ; facial tubercle not more protuberant 

 than the antennal tubercle. Mesonotum and scuteUum deep shining black, with abundant black pile j 

 the margin of the scutellum with longer hairs, scarcely differentiated as bristles ; pleuras with white pile'. 

 Abdomen shining, somewhat metallic, black, with white and dusky pile ; second segment, except the 

 smaU front angles and the narrow hind margin, and the third segment, save a large, triangular lateral 

 spot and the narrow hind margin, opaque black. Legs blaek, with white pile; the tibias and the four 

 anterior tarsi largely luteous-yellow. Wings greyish- or yeUowish-hyaline ; stigma pale yellow. 



Length 6-9 miUim. 



Eab. Mexico, Omilteme 8000 feet, Xucumanatlan 7000 feet, Sierra de las Aguas 

 Escondidas 7000 feet, all in Guerrero (E. E. Smith). 



This species may be easily distinguished from all other known American 

 it is nearest related to C. versipellis, Willist. 



4. Chilosia frontosa. 



Cartosyrphus frontosus, Bigot, Ann. Soc. Ent. Fr. 1883, p. 553 \ 

 Eab. Mexico 1 . 



MELANOSTOMA. 

 Melanostoma, Schiner, Wien. ent. Monatschr. iv. p. 213 (1860). 



Synopsis of the recognized Central-American species. 



1. Tibiae of the males on the outer side with long hairs ; pollen of 



the face with the ground-colour showing through in dots 



or ripples 2. 



Tibise of the males without such hairs or bristles ; pollen of 

 the face not dotted or rippled 3. 



2. Face moderately projecting below, in profile distinctly receding 



below the tubercle stegnum, Say. 



Face markedly projecting below, not receding below the 



tubercle fenestralum, Macq. 



3. Abdomen with yellow or yellowish markings 4. 



biol. cente.-amee., Dipt., Vol. ITL, December 1891. c 



