AKT. 2 A EEVISION OF THE GENUS PROCECIDOCHARES ALDRICH 1 1 



of them have three or four blackish bristles at the base of the 

 ovipositor, not very striking. In some specimens the apical band 

 is not connected on the third vein with the second one. 



CALLACHNA, new genus 



Allied to Procecidochares, but differs chiefly as follows: (a) The 

 second vein has an erect branch on the front side near the apex, 

 reaching the costa; (b) the single reclinate upper orbital bristle occur- 

 ring in most Trypetidae is here replaced by a group of from three to 

 five; (c) the parafacial bears a row of hairs, pale and somewhat flat- 

 tened, near its anterior edge; (d) inside the ptilinal suture at its 

 lower end, on what would be the base of the facial ridge if it were 

 better developed, is a group of very noticeable stout, white hairs, 

 which are much larger than in any species of PrececidocTiares ; (e) the 

 male has a singular swelling and expansion of the lateral abdominal 

 membrane connecting the tergites and sternites. 



Genotype. — Trypeta gihha Loew. 



CALLACHNA GIBBA Loew 



Trypeta (Oedaspis) gibba Loew, Mon. N. A. Dipt., vol. 3, 1873, p. 260. 

 Oedaspis gibba Snow, Kans. Univ. Sci. Bull., vol. 2, 1903, p. 219. 

 Procecidochares atra (part) Phillips, Journ. New York Ent. Soc, vol. 31, 

 1923, p. 137. 



Loew described the female, from Texas; Snow reported the species 

 from Douglas County, Kans.; while Mrs. PhilHps thought it a syn- 

 onym or a " freak " of atra, and did not give a definite locality. The 

 type is in the Museum of Comparative Zoology at Cambridge, Mass., 

 and was recently examined for me by Mr. Nathan Banks, who con- 

 firmed my determination. 



Male. — Ground color black; legs, antennae, and palpi dark yellow; 

 front and most of pleurae yellowish brown; eyes small and narrow; 

 front very wide, 0.61-0.66 of head width. The stout, postorbital 

 pale hairs from the middle of the eye upward about five in number 

 to occipital region where they are widely interrupted, only one pair 

 in the middle behind the ocelli. Inner and outer vertical bristles 

 black, a small tuft of black bristles on each side of front above, con- 

 siderably distant from the eye as mentioned in generic characters, 

 only two black frontals below these. A few small white, stubby 

 hairs irregularly placed above the lunule and at the sides close to eye. 

 Parafacial fully as wide as third antennal joint, whitish with a dark 

 streak extending downward from the eye ; face, including lunule, rather 

 white with a large cluster of distinct white hairs below, as mentioned 

 in generic characters. Third antennal joint more dark brown than 

 the basal ones; arista bare, the two basal joints distinct but short; 

 edge of mouth rounded, not projecting; cheek about four-fifths the 

 eye height, with a few dark hairs along the dark streak which extends 



