226 PROCEEDINGS OF THE NATIONAL MUSEUM vol. iie 



quarter the apical width of tibia, spur smaller and paler in the female. 

 Hindbasitarsus longer than the second segment but not as long as 

 2 + 3. Abdomen with tergal plates 1+2, 3, and 4, each slightly in- 

 creasing in size; pale spots (fig. 1) caused by desclerotization of cuticle, 

 lying across the boundaries between 1 + 2 = 3, and 3=4; anterior spot 

 oval, posterior one pointed laterally, both well separated from the 

 margin. Female with segments after 4 (figs. 2, 3) often retracted but 

 tergite 5 sometimes visible as a narrow transverse plate; sternites 

 (fig. 3) very reduced, 1+2 rather small and transverse, 3 somewhat 

 longer than broad, weakly dumbbell shaped (or in the Chilcales 

 specimen, diamond shaped), 4 very long and narrow, more than four 

 times as long as broad, side margins sinuate; sternite 5 transversely 

 crescentic; spu-acles 1-4 in the membrane laterally (1 hard to see 

 and very close to the thorax), 5 in the membrane between the fifth 

 sternite^ and tergite; cerci oval with short bristles. Male with ter- 

 gite 5 relatively large, somewhat better developed on the right, ter- 

 gites 6 and 7 visible on the left side; genitalia (figs. 4, 5) large; ninth 

 segment not emarginate for the reception of the cerci and the anal 

 orifice; cerci loosely attached to the ninth segment, emargination 

 between them shallow, flat bottomed; gonapophyses absent, lateral 

 lobes of forked plate short and broad, lying at the sides of the cerci; 

 forceps long, narrow, pointed, curved upward, yellowish with rather 

 long bristles on the inner sides; aedeagus with a basal stalk that ex- 

 pands distally and is angularly truncate, distally with an apical loop- 

 like sclerite, each side of which is a lateral lobe; sternites 1+2 (fig. 4) 

 represented by three small plates, the central one transverse and big- 

 ger than the other two; sternite 3 transveree with a moderately long 

 and broad rounded posterior extension; sternite 4 very transverse, 

 narrowed laterally; sternite 5 even more transverse with a central 

 desclerotized area; sternites 3 and 4 with some longish bristles. 



Ecuador: Los Kios, Pichilingue, elev. 40 m., Feb. 2, 1955, 20 cT 

 18 9 (including holotype cf and 9 allotype), E. S. Ross and E. I. 

 Schlinger, CAS; further paratypes, Guayas, Naranjal, December 

 1955, 9, Chilcales, Aug. 1, 1955, 9, R. Levi-Castillo, USNM. 



Some paratypes in my collection, including Icf , 1 9, macerated and 

 in alcohol. The females and males are associated because they were 

 the common type in the locality with the same type of prosternum. 



Sphaerocera {Parasphaerocera} trapezina, new species 



Males and females. Resembles S. ecuadoria, new species, very 

 closely but differs as follows: Size on the average slightly smaller. 



2 Young (1921, p. 260) found seven spiracles in Copromyza ( = Borborus) 

 equina Fall. I could find only five in C. sordida Zetterstedt, c?" . 



