88 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL, III 



to impression, Laterotergite I extending length of segment; with 3 

 setae. Spiracles slightly larger in first abdominal segment ; in anterior 

 half of segment, nearer to middle of sclerite in the more posterior 

 segments, Spiracular sclerite small, subovate or subcircular, Pleurite 

 large, subovate; with 2 or 3 setae (i large). Sternum subquadrate; 

 of I piece; 4 faint impressions, anterior pair meeting medially; 

 bearing from 6 to 12 setae, mostly around margins of sclerite. 



Ninth abdominal segment (fig. 20, a, b) exclusive of urogomphi, 

 slightly longer than eighth abdominal segment and five-sixths as 

 wide; almost as long as wide; sides of anterior half subparallel, pos- 

 terior half tapering caudally, making width at anterior margin of 

 caudal notch about three-fifths greatest width of segment. Dorsum 

 convex anteriorly, flattened posteriorly; sloping downward from 

 front to back. Dorsal plate (dpla) irregularly lined and wrinkled; 

 punctulate, punctures small ; 4 longitudinal impressions, 2 laterally 

 (lim) from both sides of which short impressed lines extend, and a 

 short paramedian pair (pirn) which converge posteriorly but do not 

 meet; without setae except at lateral margins which are raised and 

 carinate, bearing 3 prominent blunt "teeth," each with a long seta ; 

 transverse impression (trim) continues completely across segment. 

 Tergite continues uninterruptedly laterally and on posterior ventral 

 surface; usually with from 12 to 18 setae on each side, some issuing 

 from small sclerotized tubercles; 10 to 15 conspicuous punctures an- 

 teriorly on lateral aspect of segment. Distance between posterior 

 margin of pleural area and anterior margin of caudal notch approxi- 

 mates one-sixth to one-fifth of total length of segment, exclusive of 

 urogomphi. Pleural area (pi) large, consisting of transversely striated 

 membrane. Sternum of 2 sclerites, separated anteriorly by median 

 longitudinal suture and posteriorly by tenth abdominal segment ; each 

 sclerite usually with from 6 to 9 setae, mostly in row around tenth 

 abdominal segment. 



Urogomphi (ur, fig. 20, a, b; fig. 20, e) separate, bifid; projecting 

 prongs subequal or inner prong slightly longer. Inner prong (ipr) 

 large; projecting caudad and slightly dorsomediad, with sharp up- 

 turned tip; 2 long setae, i laterally arising from a strongly mar- 

 gined socket and i halfway along ventral aspect. Outer prong 

 (opr) usually slightly shorter than inner prong, projecting dorso- 

 caudad and slightly laterad, with short horny tip (often absent due 

 to erosion) curving anteromesad; 2 large setae, i ventrally at base 

 of prong and i arising from anterior face of prong ; sometimes a few 

 fine, short setae around distal half of prong. Undivided part of uro- 



