PSYCHE. 



DIPTERA FROM THE MESILLA VALLEY OF THE RIO GRANDE 

 IN NEW MEXICO. — I. 



BY C. H. TVLER TOWXSEND, LAS CRUCES, XEW MEXICO. 



This region has been described, in 

 dirterent papers and at different times, 

 both by Professor Cockerell and myself, 

 so that further desciiption here is un- 

 necessary. For information as to its 

 ciiaracteristics, reference may be made 

 to my first and second papers on bio- 

 geography of Mexico and the south- 

 western U. S., in the Transactions of 

 the Texas Academy of Science (1S95- 

 1S97). 



TABANIDAE. 



I. Tabanus guttatuliis Towns. 



Syn. Diacldorns guttatulns Towns. 

 Trans. Kans. Acad. Sci. 25th Ann. 

 Meet. pp. 134-5. 



Four 9 s (R. R. Larkin). Las 

 Cruces. Length, Sg to \o\ mm. This 

 is not a Diachiorus. The portion of 

 front between eyes is about 2\ times as 

 long as vertical width, the front, there- 

 fore, being comparatively wide. The 

 eyes are distinctly pubescent, but the 

 pubescence is not readily noticed. The 

 front tibiae are but little thicker than 

 the others. It probably belongs in 



Osten Sacken's section Therioplectcs. 

 The above points should be added to 

 my original description. The lateral 

 prolongations of the frontal callosity 

 above are sometimes obsolete, repre- 

 sented only by a brown spot on each 

 side of the small median callosity, which 

 latter may or may not be cut off from 

 the large frontal callositv below it. 



SYRPHIDAE. 



z. Paragus tibialis \ar. dimidiatns 

 Lev. Six $%. Las Cruces, August 

 31. On flowers of Aphantostefhus 

 arizoiiicus Gray. Length, 3 to 4 J mm. 

 Only a faint shade of brown on tip of 

 abdomen, and all with the second 

 segment more or less broadly red behind. 

 Length of the vertical triangle in one or 

 two of the specimens about twice its 

 greatest width (at posterior corners of 

 eyes) , but in the others not over one and 

 one-half times. It thus seems certain 

 that this character will not separate the 

 American from the European forms. 

 See paper on White Sands diptera, for 

 notes on this species. 



