94 DIPTEEA. 



Female. It differs from the male as follows : — 



1. There are no white lateral spots on the third abdominal segment ; the rufous hair 

 along the sides of the abdomen encroaches upon the spaces occupied in the male by those 

 white spots ; there is no rufous pile on the venter, but traces of white scaly hairs on the 

 last ventral segment. 



2. The legs are altogether black. 



3. The apex of the wings is hyaline, in other words the subhyaline spaces within the 

 apical cells (including the expanded end of the marginal) are not separated here by 

 thickly clouded veins ; there is no hyaline spot within the anal cell ; that at the end of 

 the axillary cell is small. 



N.B. — I have seen Wiedemann's type specimen in Berlin, and the identification is 

 certain, the discrepancies of the description notwithstanding. The pattern of the wings 

 in this species is variable, especially in the intensity of the clouds on the veins near the 

 apex. 



6. Hyperalonia kaupi. 



Ewoprosopa kaupi, Jaennicke, Neue exot. Dipt. p. 32, t. 2. f. 17. 

 Hab. Mexico, Tehuacan (Sumichrast). 



A specimen from the above locality in Prof. Bellardi's collection, and another (?) in 

 the British Museum, agree with the description. The species differs from its congeners 

 in having five submarginal cells. 



STONYX, gen. nov. 



Three submarginal cells ; third joint of the antennae short, onion-shaped, with a very long style, not bisected 

 by a suture, and ending in a minute appendage, the first joint very short. Legs delicate ; the difference 

 in size and strength between the front and hind pairs less striking than in Exoprosopa ; front tibiae beset 

 with spinules ; front tarsi of the ordinary structure, that is, with distinctly marked joints, and a brush of 

 microscopic bristles on the underside of the first joint ; front ungues not unusually small ; no tooth at the 

 base of the ungues ; no pulvilli. Proboscis projecting considerably beyond the oral margin (in the species 

 before me the length of the head or more) ; lips narrow. The interval between the eyes, on the vertex, 

 comparatively broad in both sexes. The male forceps withdrawn within the body, in the usual, unsym- 

 metrical position. The ovipositor of the female has the usual coronet of spinules, but very small, usually 

 withdrawn, and difficult to perceive. 



The three known American species I refer to this genus are clothed with a dense 

 reddish-brown silky tomentum, not variegated by cross-bands or spots, like most 

 Exoprosopoe ; they have the wings brown, variegated with hyaline. 



That these species cannot remain in the genus Exoprosopa is evident ; but whether 

 the definition of the genus Litorhynchus, introduced by Macquart for certain African 

 species, should be applied to them cannot be settled without comparison of specimens. 

 The fact that Loew (Sudafr. Dipt. p. 223) rejects the genus seems to prove that it is 

 not identical with Stonyx, because he would not have rejected the latter. (Compare 



