ASILUS.— NEOMOCHTHEBUS. 209 



2. Asilus midas. 



Asilus mydas, Brauer, Sitzungsber. Ak. Wiss. Wien, xci. p. 387, figg. 1, 1 a (1885) \ 

 Hab. Mexico, Ciudad in Durango 8100 feet (Forrer), Cuernavaca 1 . 



This recognizable species has been figured, but not described, by Dr. Brauer, in 

 order to illustrate a case of mimicry between it and a Midas [M. rubidapex, Wiedem.) 

 from the same locality. A. midas is easily described : it is altogether velvety-black, 

 with black hairs and bristles ; the face with a tuft of white hairs on each side, on the 

 cheeks, in the male ; wings of a rich reddish-yellow, brownish at the base, the alulee 

 brown, the apical margin brownish ; pulvilli of the usual fulvous colour ; male forceps 

 rather large and stout ; ovipositor short ; the eighth abdominal segment shorter than 

 the preceding one, smooth, shining, black, sparsely beset with hairs ; the ovipositor 

 proper with short valves, and beset with yellowish hairs. The venation like that of the 

 preceding species ; the second posterior cell bulging out and encroaching upon the first. 



NEOMOCHTHERUS. 



Neomochtherus, O. Sacken, Catal. N. A. Dipt. 1878, p. 82. 

 Mochtherus, Loew, Linn. Ent. iv. p. 58 (1849) . 



1. Neomochtherus plebeius, sp. n., s $ . 



Brownish ; thorax with brown stripes ; abdomen dark brown, with the posterior margins of the segments 



pale ; legs yellowish-red, the tarsi darker. 

 Length about 18 millim. 



Hab. Mexico, Northern Sonora {Morrison). 



Face yellowish-white sericeous, flat, but the mouth fornicate and projecting in 

 profile in front of the eyes ; no perceptible facial tubercle ; mystax with a few whitish 

 bristles ; a few whitish bristles also along the edge of the mouth ; beard very soft, 

 white ; front yellowish pollinose ; ocellar bristles microscopic ; occiput yellowish-white 

 pollinose ; bristles of the upper occipital orbit yellowish or black ; antennae black, the 

 second joint brownish; palpi black, with a few white hairs at the tip. Thorax with a 

 dark brown, opaque, dorso-central stripe, and a more or less distinct pollinose dividing 

 line ; lateral stripes distinct, but more feebly marked ; the intervals and the scutellum 

 brownish-yellow pollinose ; pleurae greyish pollinose. Halteres pale yellowish. Abdo- 

 men : first segment yellowish pollinose, its base greyish ; the remaining segments dark 

 brown, with pale orichalceous hind margins, the breadth of the margins less than one 

 fourth of the length of the segment ; lateral margins greyish pollinose. Forceps black, 

 shining, not broader than the abdomen, moderately beset with blackish and whitish 

 hairs. The segments 8 and 9, forming the ovipositor, compressed from the sides, black, 

 shining. Legs smooth ; the closely appressed pile visible only under a strong magni- 

 fying-power ; the bristles few ; yellowish-red, the femora with more or less distinct 



biol. centr.-amer., Dipt., April 1887. 2 e 



