DIPTERA. 



329 



5. Asilus (Heligmoneura) xanthocerus, sp. n. 



6 2 • Head nearly white throughout, with the hristles and hair also white. Antennae light yellow ; third 

 joint short, not longer than the first, the arista more than twice as long. Gibbosity of the face slight, 

 confined to less than the lower half. Thorax opaque, light yellowish-white, with the pleurae whiter ; 

 the black bristles of the mesonotum extend a little in front of the middle ; the usual median stripe is 

 dark brown in front, but becomes evanescent behind, leaving two slender lines ; the lateral spots are 

 feebly indicated. Scutellum with two bristles on its margin. Abdomen reddish-yellow, its shining 

 appearance only slightly obscured by the pollen ; first two segments largely brownish ; the third and 

 following segments have each a slender, oval, black, longitudinal spot in the middle; forceps of the male 

 and the small ovipositor shining black ; lateral bristles of small size, yellow. Legs wholly light yellow. 

 Wings hyaline, broadlv clouded at the tip and narrowly behind ; the proximal end of the second 

 submarginal cell is a trifle more distant than is that of the second posterior cell. Length 16-18 milhm. 



Hab. Mexico, Dos Arroyos, Rio Papagaio, Venta de Zopilote, and Tierra Colorada 

 in Guerrero (H. H. Smith). 

 Twenty-five specimens. 



6. Asilus (Heligmoneura) melanocerus, sp. n. 



S $ . Front narrow above ; yellowish- and greyish-pollinose. Face narrow above, a little wider below, 

 moderately protuberant ; densely yellowish-grey-pollinose ; mystax white, a few black bristles on the 

 upper part of the convexity. Antennas black ; third joint as long as the first two joints together, and one- 

 half longer than the style. Mesonotum greyish-yellow-pollinose, with the usual brown stripes, the middle 

 one geminate, the lateral ones in the form of elongate-oval spots ; the bristles not reaching in front of the 

 middle, black. Scutellum with two strong black bristles on its margin. Pleurae grey-pollinose. 

 Abdomen, viewed obliquely, opaque yellow; viewed vertically, subshining black, except the hind margins 

 of the segments; bristles before the hind margins of the segments and on the sides yellow; hypopygium 

 black, shining, not clubbed ; ovipositor, beginning with the eighth segment, shining black. Legs yellowish- 

 red or reddish-yellow, with black and yellow bristles ; tarsi, and sometimes the tibiae, blackish at the 

 extremity ; hind femora rather slender and elongate. Wings yellowish-hyaline, broadly clouded at the 

 tip and along the posterior margin. Length 17 millim. 



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

 Eight specimens. 



7. Asilus (Heligmoneura) dolichomerus, sp. (var. ?) n. 



j $ . In all respects like A. melanocerus, except that the femora are wholly deep shining black. The tibiae 

 are often blackish at the extremity. Length 15-16 millim. 



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

 6000 to 9500 feet {H. H. Smith). 



Thirty-five specimens. The constant and striking difference in the colour of the 

 femora would seem to indicate a specific distinction, though I can discover no other 

 peculiarities. 



8. Asilus (Neoitamus) nigrocaudatus, sp. n. 



rf $ . Face and front light yellowish-grey ; bristles of the front, antennae, and convexity of the face black ; 

 bristles of the oral border white. Antennae black ; third joint about as long as the first two together ; 

 arista a little longer than the third joint. Facial gibbosity strong and abrupt. Thorax light yellowish, 



biol. centk.-amee., Dipt., December 1901. 2 u 



