2 PROCEEDINGS OF THE NATIONAL. MUSEUM vol.68 



Curiously enough the nearest resembling form of proboscis found 

 in the literature is that of a fly likewise from Bolivia, described 

 by Professor Hendel under the name of Drosophilura cavdata;^ 

 but this fly was subsequently recognized as the female of Zygothrica 

 dispar Wiedemann, 1830,^ and as I can see in specimens from 

 Brazil in my collection its proboscis is in reality very different from 

 that of the new genus here described, and normally shaj)ed. 



Another striking feature is what I assume to be the exceedingly 

 developed prelabrum or anterior swelling of the fulcrum of the 

 proboscis (fig. 2, prl.) In other members of the family it is much 

 less developed and of usual form, as figured by Wesche (who calls 

 it labrum) for Borhorus equinus^^ or by Peterson (who calls it 

 tormae) for the same species,^ or by Frey for Sphaerocera suhsul- 

 tans.'^ In other genera of Acalyptratae the prelabrum is conical and 

 projecting, for example in Coelopa; and even in the Calliphorid 

 genus Bengalia it is shaped as a prominent lamella; but I know no 

 other fly in which it presents such a development as an entirely 

 exposed organ. 



PYCNOPOTA, new genus 



Species of elongate body and of rather small size, with cylindro- 

 conical abdomen and with the legs rather slender and simple in both 

 sexes. 



Head (fig. 2) not broader than the thorax, in profile a little more 

 high than long, in front view distinctly more broad than liigh. 

 Occiput convex, but very little prominent, the distance from the 

 neck to the vertex being distinctly shorter than the length of the 

 frons; vertex not carinate, gently rounded. Frons flat, parallel- 

 sided or only a little broadening forward, a little longer than broad ; 

 ocellar spot rounded, small, but very little prominent, with 3 well- 

 developed, equidistant ocelli ; middle stripe twice as broad as one of 

 the parafrontalia, with parallel sides, quite bare, with less differ- 

 entiated triangle, with the anterior broader a little concave and pro- 

 duced above the root of the antennae; lunula very small, visible only 

 from in front; parafrontalia curved below anteriorly, with only 

 3-4 isolated hairs between the frontal bristles. Face short and 

 deeply concave, with distinct middle keel and with broad and prom- 

 inent mouth border; parafacialia linear, peristomialia short but 

 rather broad in front, only a little more narrow than the third 

 antennal joint. Eyes with rather broad areolets, quite bare; they 

 are regularly rounded on the upper lialf, but in the lower half they 

 are rather narrowed on account of the deep concavity of the face. 



2Entom. Mitteil., vol. 2, 1913, p. 387, fig. 2. 



5 A. li. Sturtevant, Proc. U. S. Nat. Mus., vol. 58, 1920, pp. 155-158. 

 *.Tourn. Ro.yal Micr. Soc, 1904, p. 41. pi. 8, fig. 11. 



s Illinois Biolog. Mon., vol. 3, 1916, p. 221, pi. 4, fig. 63 ; pi. 10, fig. 188 ; pi. 15, fig. 

 342 ; pi. 24, fig. 565. 



* Acta Soc. pro Fauna et Flora Fennica, vol. 48, 1921, pi. 4, fig. 49. 



