348 DIPTERA. 
MUSCIDE ACALYPTERA. 
Some remarks on this division of the Muscide will be found on p. 2 of this volume. 
In general, the Acalypteree may be known from the Calypteree by the absence of 
tegule, a few genera only having these organs more or less developed. In the 
venation of the wings the species of this division approach the Anthomyine, the 
fourth vein not being curved upwards to an apical cross-vein. The front is broad in 
both sexes; the eyes are never coalescent in the males and mostly of a rounded form ; 
the transverse suture is usually inconspicuous or wholly absent. 
The Acalypterz include a great diversity of forms, and therefore are divided into a 
large series of groups. The classification of Schiner (Fauna Austriaca, ii.) and Loew 
(Monogr. of the Diptera of N. America, i.) is, save in a few cases, here followed. 
Group CORDYLURINZ. 
The principal characters of this group, which by its general facies is most nearly 
allied to the Anthomyine, are:—Lateral borders of the front with bristles over their 
whole length ; oral margin distinctly armed with vibrisse; abdomen elongate; body 
and legs often hairy in the male; tibie with spurs; first vein of the wings double, the 
auxiliary vein being separated from it; the basal cells perfectly developed. 
‘Iwo genera only of this group are represented in the Mexican collections before me. 
Abdomen cylindrical, in the male enlarged at the extremity, with the genitalia 
usually prominent ; proboscis weak, with distinct terminal lips; legs elongate 
and slender, with small foot-claws and pulvilli . 2. . 2. 1. 1. ee «© Cordylura. 
Abdomen more oval, somewhat flattened, the male genitalia less conspicuous ; 
proboscis horny, often pointed or with small terminal lips; legs robust, the 
foot-claws and pulvilli more developed . . . . . . «+ + + + + + 6+ ©6Seatophaga. 
Both genera contain species with a plumose arista and others in which the 
arista is bare or nearly so. For the Cordylure with a non-plumose arista Macquart 
has established the genus Cleigastra, which has been adopted by Schiner for the 
European species. Loew, on the contrary, who has described several North- 
American forms, includes species with a bare, as well as others with a plumose arista, 
under the one genus Cordylura. 
The species of Scatophaga with a bare arista have been generically separated by 
Robineau-Desvoidy under the name Scatina; in Schiner’s work they form merely a 
subdivision of the genus Scatophaga. 
CORDYLURA. 
Cordylura, Fallén, Specim. entom. nov. Dipt. disponendi method. exhib. (1810). 
Of this genus I have examined three Mexican species, all apparently undescribed. 
