MIDAS. 71 



is shorter and ap pressed on the second segment; (2) the alula, which mM.rubidapex is 

 blackish, like the whole base of the wing, is reddish here — this character becomes 

 especially apparent when the wings are folded over the back of the insect and the large 

 alulae cover the scutellum ; (3) in M. rubidapex the limit between the reddish-yellow, 

 opaque anterior and the subhyaline posterior portion of the wing is marked by an 

 irregular, but continuous blackish line of cloud, which runs from the costa towards the 

 anal angle of the wing — in M. dives this continuous line of cloud does not exist, only 

 disconnected vestiges of it are visible in the shape of small clouds in some of the cells. 

 Prof. Bellardi, in his description of M. rubidapex, mentions a specimen he had received 

 from the Museum in Paris, which had the second abdominal segment clothed with a 

 yellow tomentum ; this was probably M. dives. Mr. Westwood gives no locality ; 

 Dr. Gerstaecker had M. dives from Brazil ; it agrees with our specimens. 



3. Midas decor, sp. n., <j . 



Black, shining; a pair of abbreviated, indistinct hoary lines on the front part of the thorax; wings pale 



yellowish-brown, somewhat darker anteriorly, the fork of the third vein rather ventricose. 

 Length 21 millim. 



Hab. Panama, Bugaba 800 to 1500 feet (Champion). 



Not unlike M. crassipes, Westw. (Arcana Ent. i. t. 13. f. 3, from % North America), 

 in shape and colour, but much smaller ; the abdomen has the same shape, that is, its 

 sides are almost parallel, with a slight coarctation a little beyond the base ; the forked 

 cell is much more ventricose than in the figure of M. crassipes ; the weakness of the 

 hind femora, the presence of the hoary stripes on the anterior part of the thorax, of a 

 tuft of white hairs above the hind coxae, &c., seem to prove the specific distinctness. It 

 cannot be the same as M. bitceniatus, Bell., which has thoracic stripes much more 

 distinct, the face with hoary stripes along the orbits, and the abdomen conical. M . 

 carbonifer, O. Sack. Catal. N. Am. Dipt. p. 236 (New York), has an opaque thorax and 

 darker wings ; M. virgatus, Wiedem., has the lateral thoracic margins and the abdominal 

 incisures whitish hoary, the wings more evenly brown, &c. 



Head black, the face shining ; all the hairs upon it black, except a few white ones on 

 the underside of the occiput ; white hairs in the mystax are perceptible in a certain 

 light only ; no hoary stripes along the orbits, except a trace on the occipital orbits ; 

 antennae black. Thorax black, the dorsum shining, with two feebly marked hoary 

 stripes (visible in an oblique light only) on the anterior portion; pleurae opaque, 

 With a slight hoary bloom on their lower parts, above and between the coxae; 

 the latter black, shining. Legs black ; hind femora very little incrassate, but with very 

 sharp spines on the underside ; terminal hook of the tibiae small ; a tuft of white hairs 

 above the hind femora. Halteres black. Abdomen black, shining. Wings tinged with 

 pale yellowish-brown ; subcostal, marginal, and a part of the first submarginal cells 

 a little darker brown ; second submarginal cell expanded before the middle, coarctate 



