NO. 1938. THE DIPTEROUS FAMILY PHORID^—MALLOCH. 509 



Genus COMMOPTERA Brues. 



The onl,y species as yet described in this geuus is solenopsidis 

 Brues, from Texas. It occurs in nests of Solenopsis geminata. 

 Unrepresented in collection. 



Genus ACONTISTOPTERA Brues. 



In 1902, Brues * described an insect discovered in a nest of Eciton 

 opacithorax Emery, at Austin, Texas, and placed it in a new genus, 

 the principal characters of which are: Head broad, more than one 

 and one-half times as wide as widest part of thorax, upper surface 

 of head with two central macrochgetse, eight marginal ones on lateral 

 and posterior edges, one over each eye, a bunch at front angles, and a 

 regular series of closely placed ones along the front between the 

 antemise; thorax small, narrowed posteriorly, pleurae visible from 

 above, wings about as long as width of thorax, arcuate, of nearly 

 equal width, with a few short bristles at base on external margin, at 

 about middle these suddenly enlarge until at the tip the}^ are more 

 than twice as long as the wing, there are about 10 of these macro- 

 chsetae which are all strongly, thickly, and almost scaly pubescent. 

 The only species described so far is A. melanderi Brues. 



ACONTISTOPTERA MEXICANA, new species. 

 Plate 40, fig. 6; plate 41, fig. 1. 



Female.— Di&ers from the description and jfigure of melanderi 

 Brues in the much stronger bristling throughout. The bristles on 

 posterior row are not so near the edge as shown by Brues, there 

 are two on the sloping portion of the frons over the antennae, there 

 are three large bristles on either side of epistome that do n^t form 

 part of the row mentioned in Brues 's description of his species, there 

 are several very strong curved macrochsetse on either lateral mouth 

 edge, and the arista is plumose, the anterior pair of dorsal thoracic 

 bristles are behind the second pair of lateral bristles, and much wider 

 placed, the vdngs have no regularly placed small bristles on basal 

 half, and the series begins to enlarge very suddenh' at about one- 

 third from base, the macrochsetse being of almost equal strength in 

 the whole series of 10-12; in color and other respects as melanderi. 



One female, Cordoba, Mexico, April 21, 1908, Dr. A. Fenyes. 



Type.— C&t. No. 14903, U.S.N.M. 



1 American Naturalist, vol. 34, p. 373. 



