Art. 23 GENUS CYLINDROM YIA MEIGEN ALDEICH 17 



Antennae rather small, blackish, the arista short. Thorax black, 

 with a distinct pollinose spot on the humerus extendin<]^ almost to 

 the suture, and on the sides with silvery pollen on all of the coxae 

 and extending vaguely above the first and second ones. Sterno- 

 pleural 2, with an additional small one on one side in 1 male. Abdo- 

 men broadly dark red on the sides. Wings rather narrow, evenly 

 infuscated from front to back; the fourth vein with a long branch 

 at its bend, its last segment far from the apex of the wing. 



Male. — Claws and pulvilli all elongated, second principal segment 

 of the abdomen a little swollen along the median line below, the 

 third segment with a flattened V-shaped opening toward the geni- 

 talia. Genital segment blackish, the hind forceps united, of rather 

 soft texture, deeply grooved behind, straight almost to the apex, 

 where they bend sharply forward and are not very sharp. Anterior 

 forceps concealed by a long swollen yellow lobelike expansion of 

 the side of the last genital segment, so that only the tips, which 

 are strongly bent forward and rounded, not sharp, are visible. Front 

 tarsi plain. 



Female. — Front tarsi elongated and distinctly flattened beginning 

 with the second joint. The second principal segment of the abdomen 

 a very little swollen on the under side, somewhat less than in the 

 males. The genital segments black, the last one ending w^ith a rather 

 square shoulder which bears an almost imperce^^tible tooth, there 

 being no hooklike structure developed. 



Length. G to 7 mm. 



Described from two males and two females collected at Marshall 

 Pass, Colorado, by the writer on July 28, 1908, at an altitude of 

 10,856 feet. 



One of the females possesses very minute but unmistakable palpi. 



7V/^e.— Male, Cat. No. 28280, U.S.N.M. 



CYLINDROMYIA NANA Townsend 



(Figs. 14, 19, 20) 



Odontocyptera nana Townsend, ,Jouni. New York Ent. Soc, vol. 23, 1915, 

 p. 233, female. 



The parafrontals and parafacials silvery, the brown frontal stripe 

 about as wide in the middle as the width on both sides combined. 

 Parafacial almost twice as wide as the third antennal joint; the 

 position of the eye a very little more vertical than usual. Thorax 

 with considerable silvery pollen, viewed from behind there is a 

 broad black stripe outside the dorsocentrals before the suture and a 

 slender stripe on the inner side of the same bristles which does not 

 reach the suture. The abdomen varies a good deal in the amount of 

 pollen that it shows and the red portion varies in extent but tends 



