202 DIPTEEA. 



smaller, the pollen on the face is yellowish-white, and not yellow ; the whole third 

 abdominal segment of the male is silvery (if I understand the description), and not its 

 posterior half only, &c. 



I have a species from Texas not unlike E. rapax, and with yellow hair on the palpi ; 

 but it is larger, the wings comparatively shorter, the tibiae reddish on the upperside 

 of the base, &c. 



6. Erax cinerascens. 



Erax cinerascens, Bellardi, Saggio &c. ii. p. 39, t. 2. f. 10 l ; Schiner, Verh. z.-b. Ges. Wien, 1867, 



p. 394. 

 Erax furax, Willist. Trans. Am. Ent. Soc. xii. p. 67 2 (synonymy apud Williston, in litt.). 

 Erax albibarbis, Macq. Dipt. Exot. i. 2, p. 118 3 . 



Bab. United States 23 . — Mexico (Salle 1 ), Northern Sonora (Morrison), Presidio 

 (Forrer), Tuxpango near Orizaba (Sumichrast 1 ). 



This insect will be easily recognizable from Prof. Bellardi's figure; some clerical 

 error renders this author's description of the abdomen obscure, and that of Williston 

 will have to be relied upon. Schiner's description, although detailed, was drawn from 

 a single specimen. The abdominal black spots are variable in size and outline. The 

 white hairs on the palpi are characteristic. 



E. cinerascens must not be confounded with the Mexican E. tricolor, Bellardi (I. c- 

 p. 40, t. 2. f. 12), which is very like it in general appearance, but has black hairs in 

 its mystax. 



Macquart's description of E. albibarbis (I. c.) reads very much like that of E. cineras- 

 cens, the white hairs on the palpi being especially convincing ; this author describes the 

 male. I do not think that Schiner (I. c. p. 395) was right in identifying the female 

 specimen he had with Macquart's description. At any rate Bellardi's specific name, 

 justified as it is by a figure, should be retained. 



7. Erax ?, e $. 



Eab. Costa Eica, Cache (Rogers). 



I have four males and one female of this rather ordinary-looking species. It seems 

 to be related to E. affinis, Bellardi, but the femora of the latter have some red at the 

 sides and at the tip, which is altogether wanting in these Costa Bican specimens ; the 

 description of the abdomen also does not agree. 



8. Erax prolificus, sp. n., <? $ . 



Male. Facial tubercle prominent, the hairs upon it white, mixed with some black, and sometimes with some 

 yellowish, bristles ; palpi and the hairs upon them black ; tuft on the cheeks white ; antenna black, the arista 

 longer than the third joint ; the strong bristles on the upper occiput yellow, or reddish-yellow, sometimes 

 mixed with black, or altogether black. Thorax : dorsum more or less yellowish-grey or brownish-grey ; 

 dorso-central stripe brown, comparatively narrow, distinctly marked ; its median line bearing a crest of short 



