DIPTEEA. 373 



1. Hybos typicus, sp. n. 



c? $. Black- cinereous, slender. Face dusted with silvery-grey. Antennae black, short; third joint oval, not 

 longer than the first ; arista slender, equal in length to the eye-height. Eyes contiguous below the 

 antennae. Proboscis black, but little shorter than the height of the head. Mesonotum prominent, black, 

 shining through the coating of brown dust ; pleurae cinereous-black. Halteres yellow. Abdomen 

 slender, piceous, with loose whitish hairs, slightly pubescent, especially towards the apex. Genital 

 apparatus small, not giving the abdomen a club-shape, with two projecting filaments; somewhat similar 

 externally in the two sexes. Legs slender, piceous, shining, with scattered pubescence ; knees lighter ; 

 front tarsi long, metatarsus equal in length to the tibia ; middle tibia? with two long slender bristles on 

 the external side (one at the basal fourth and one at the centre), and with three on the inner side (at the 

 middle, outer fourth, and tip) ; hind femora reaching to about the tip of the abdomen, moderately 

 thickened, not evidently serrate beneath, but with a series of about six darker hairs, besides the 

 pubescence ; hind tarsi not toothed beneath. The males have the front tibiae on the posterior side, and 

 the metatarsi on both sides, ciliated with long hairs. Pulvilli small. Wings hyaline, subquadrate, 

 obtusely rounded at the apex, anal angle not strong ; veins yellowish ; third vein terminating beyond the 

 middle, parallel with the fourth ; stigmal spot not well-developed, not filling out the apex of the marginal 

 cell ; discal cell broad ; anal vein not evident. The fine hairs around the margin of the wing are not so 

 closely placed as usual. 



Length 4 - 5 millim., of the wing 4 - 5 millim. 



Hab. Mexico, Omilteme and Sierra de las Aguas Escondidas in Guerrero 8000 to 

 9500 feet (H. H. Smith). 



Two males and three females. 



2. Hybos mellipes, sp. n. 



5 . Black, shining, moderately strongly yellow-pilose. The two parts of the antennae are subequal in length ; 

 arista shorter than the eye-height. Eyes contiguous below the antennae, leaving a small subantennal 

 triangular space shining black. Mesonotum shining black, moderately strongly pilose. Pleura black, 

 shining, not cinerascent. Pedicel of halteres black (knobs wanting). Abdomen shining black, robust, 

 compressed at the base and depressed apically, not unusually hairy; ovipositor with short bristles. 

 Legs, except the tarsi, shining black, strongly hairy ; posterior femora incrassate, reaching the tip of 

 the abdomen, not strongly spinulose beneath ; first two joints of the tarsi yellowish, the remainder 

 blackened. The hairs of the legs are longer laterally, so as to give the legs, especially the tarsi, a ciliated 

 appearance when viewed from the front. Wings narrow, wholly hyaline, except for the fuscous stigma, 

 which completely fills the outer third of the marginal cell ; veins strong ; discal cell narrow. 



Length 4 millim., of the wing 4 millim. 



Hab. Mexico, Omilteme in Guerrero 8000 feet (H. H. Smith). 



3. Hybos triplex. 



Hybos triplex, Walk. List Dipt. Brit. Mus. iii. p. 486 (1849) l . 

 Hybos purpureus, Walk. loc. cit. p. 486 2 . 

 Hybos duplex, Walk. loc. cit. p. 486 3 . 

 Hybos subjectus, Walk. loc. cit. p. 487 4 . 



Hab. North America 1_4 . — Mexico, Vera Cruz, Teapa (H. H. Smith), Yucatan 

 (Gaumer). 



Four specimens taken in different parts of Mexico differ among themselves and from 

 examples of //. triplex from the United States. These differences are so slight that 



