NO. 1571. DRAGONFLIES OF BURMA AND SIAM- WILLIAMSON. 803 



stripe; metepimeron largely pale, narrowly edged in front with black, 

 and a small black spot on its posterior border; pectus shaded with 

 brown and black. Legs slender, black, the first femora and coxse 

 with an inner gray stripe; wings hyaline; stigma brown. 



Abdomen slender, largest basally, slightly dilated apically ; segments 

 measuring in length a})out as follows : 1,1 mm. ; 2, 2 mm. ; 3, 4 + mm. ; 

 4,4 + mm ; 5, 4.5 mm. ; 6, 4 mm. ; 7, 3 + mm. ; S, 2 + mm. ; 9,2+ mm. ; 

 10, 0.75 mm.; appendages, 0.75 mm. Color black, marked with 

 greenish yellow as follows: A dorsal spot and a large inferior lateral 

 spot, not reaching the anterior border, on 1 ; a narrow dorsal longi- 

 tudinal trilobecl spot, a lateral spot covering the auricles, and a large 

 subapical lateral spot, the 2 lateral spots joined along tlie inferior 

 border, on 2 ; a narrow longitudinal dorsal stripe on 3, widening basally 

 and not reaching the apex; a similar stripe on 4 and 5, the dorsal 

 stripe shortened apically and widened basally into an almost complete 

 ring; on 6 the basal ring is practical!}^ complete, about one-eighth the 

 length of the segment, and with the dorsal stripe reduced to a small 

 acute triangle; on 7 the basal ring is complete (that is, extending to 

 the inferior margins of the segment) , covering about one-sixth of the 

 segment, and without a trace of the dorsal stripe; 8 with the merest 

 trace of a basal ring; 9 with a little less than the apical dorsal half or 

 third clear yellow, the pale area a low, rounded triangle in shape, with 

 its apex dorsal and anterior, its base formed by the posterior edge 

 of the segment and not reaching the inferior margin ; this spot is the 

 striking feature iii the coloration of the abdomen, suggesting Gomjihus 

 melxnops and its allies, all larger species. Appendages black. Con- 

 siderable variation in the development of the longitudinal middorsal 

 abdominal stripe must be expected. (See fig. 28.) 



Described from three males collected by Mr. R. A. Earnshaw.'* 



Genus PLATYGOMPHUS De Selys. 



Thi-ee species, one of them cjuestionably, have been placed in this 

 genus by De Selys. P. dolabratus De Selys occurs in India; P. fex 

 De Selys in Burma; and P.f occultus in China. In dolahratus the 

 basal yellow rings on segments 3-7 are confluent with the dorsal 

 lanceolate spot on each, segment; in occultus the dorsal spots are 

 narrower and are isolated; and in fex the dorsal spots on 5-7 are 

 wanting. (See figs. 30 and 31.) 



12. PLATYGOMPHUS FE^E De Selys. 



"Bhamo en juillet et aoiit (Fea)." Not seen by me. Only the 

 male is Imown. The followmg brief description is condensed fi-oin 



o These specimens were originally described in this paper as representing a new 

 species. In the opinion of Prof. F. Foerster, with whom I have corresponded on the 

 matter, and to whom I have sent a specimen from Burma, the species from Burma 

 and Tonkin are identical. Moreover, M. Rene Martin seemed undecided as to the 

 distinctness of the two, so my specimens are here referred to vermiculatus. 



