ART. 9 DIPTERA FEOM AMERICA, ASIA, AND JAVA AL.DRICH 21 



First and second abdominal segments each bearing one pair of 

 median marginals ; second and third with one pair of smallish discals, 

 which are quite far forward on the yellow pollinose portion; third 

 with a marginal row, the middle pair very large and stout; fourth 

 segment with irregular bristles extending forward nearly to the 

 base, no distinct row on posterior margin. The terminal ventral seg- 

 ment when exposed appears as a cylindrical tubular structure, not 

 very long, bearing at its apex a minute, shining black prolongation, 

 grooved above, bearing microscopic hairs. Legs black, middle tibia 

 with one bristle on the outer front side and one flexor; hind tibia 

 with an inconspicuous row of small bristles and two larger ones 

 rather far apart almost dividing the length into thirds. Wings a 

 little brownish ; third vein with two to four bristles at base ; fourth 

 vein with a round oblique curve, the apical cross vein more slender, 

 straight for two-thirds of its length and almost parallel with the 

 margin, then gradually curved toward the tip, joining the costa 

 quite close to the tip a little distance from the third ; hind cross vein 

 suberect, joining fourth at two-thirds of the distance from the small 

 cross vein to the bend. Hind calypter light brownish with pale 

 margin ; the front one white and subtransparent. 

 Length, 8-9 mm. 



Male. — Front at level of anterior ocellus 0.27 of head width; no 

 orbitals, third antennal joint a little broader than in female, of the 

 same length; palpi distinctly flattened and a little widened at tip, 

 but lacking the pore which is so striking in the female; eyes with 

 same pilosity as in female. Genitalia small, black, the inner forceps 

 straight, slender and close together, the outer slender and almost as 

 long; penis black, slender, with a delicate white flap on front at 

 tip. Claws and pulvilli moderately long. 

 Paratypes.—F^m^lQ, U.S.N.M. No. 43691. 



Remarks. — Described from five females and one male, reared at 

 Wanaina, Northwest District, British Guiana, March, 1931, by J. 

 G. Myers, from Castnia Ucoides Boisduval. The specimens were re- 

 ceived from the Imperial Institute of Entomology, to which the type 

 female, allotype male, and two paratype females are returned. 



The peculiar depression, or perhaps a sensory pit, in the palpus 

 does not occur in any other tachinid known to me. It occurs only 

 in the female. The species is distinguished by rather stout bristles 

 throughout. I have compared the type series carefully with Zenillia 

 lihatrix Panzer (det. Bezzi) and find it agrees well except in having 

 a single bristle on the anteroventral side of the middle tibia. No 

 fine hairlike bristles extending up facial ridges, and in the visible 

 structures at the tip of the abdomen in the female; in libatnx the 

 terminal organs are concealed in our specimens by closure of the 

 fourth abdominal segment in a longitudinal slit. 



