224 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. 53. 



Mesothorax dorsally brown to beyond the humeral suture, marked 

 with yellow as follows: Mesothoracic semicollar except for a slight 

 interruption at middorsal carina ; a line along middorsal carina from 

 crest to collar; a pair of dorsal stripes one-third to one-half of a 

 millimeter in width, divergent anteriorly and uniting with ends of 

 semicollar; a narrow, slightly sinuous antehumeral stripe, inter- 

 rupted above,^ the part above interruption a wider spot; and the 

 posterior part of antealar sinus. Lobes between wings yellow. Meso- 

 thorax and metathorax laterally yellow, except an interrupted nar- 

 row stripe on first lateral suture, a narrow stripe on second lateral 

 suture, and other markings as in diagram (pi. 27, fig. 2) ; ventrally 

 yellow. Legs dark brown, front femora inferiorly and coxae 

 yellow; hind femora extending to about the center of abdominal 

 segment 2, armed with numerous short spines, the hairs inconspicu- 

 ous. Wings (pi. 27, fig. 1) hyaline; veins black, pterostigma 

 brown, membranule gray; two cells between A^ and J. 2 at their ori- 

 gin, the proximal and anterior of these the first postanal cell, the 

 other the distal part of the divided second postanal cell; the first 

 postanal cell not divided; neither A^ nor A, distinctly angled, two 

 rows of cells between them to the wing margin.^ 



Abdomen black or dark brown, yellow as follows: On segments 

 1 and 2, a middorsal stripe, narrowed apically on 2, and a lateral 

 stripe including the auricles on 2; on base of 3, a small dorsal 

 spot, pointed behind, and a larger lateral one; on base of 4 to 

 7, a similar dorsal and a small lateral spot; on 8 and 9, a broad 

 lateral patch; 10 ventrally. Segments 7 to 9 moderately expanded, 

 narrower than the thorax; segment 8 slightly longer on dorsal than 

 on ventral side ; ^ 8 longer than 9 ; hind margin of 10 somewhat pro- 

 duced middorsally. 



Superior appendages (pi. 28, figs. 1, 2, and 3) dark brown or black, 

 a little longer than segment 10, acute apically, bearing a small, sym- 



^ This Interruption is narrow and perhaps may not always occur. 



-The characters in the postanal cells in the genus Oomi)hus have been studied by 

 Mr. Williamson and the results published by him. (See Williamson, E. B. "The sub- 

 genus Stylurus Needham : Selys' groups VI and VII of the genus Gomphus (Odonata). 

 and on the postanal cells of the latter." In Traus. Amer. Eut. See, vol. 27, pp. 205-217, 

 pis. 8, 9. May, 1901. Gomphus parvidens falls under 1, 1', and 1" in Mr. Williamson's 

 table, page 215. 



The following corrections should be made in his paper : 



Page 205, lines 13 and 16, for second read first. 



Page 214, under the heading, " North American species," in line beginning " 6. O. sor- 

 didus," for «p. a. read s. pa. 



In key, page 215, in referring to branches of anal vein, throughout for first read 

 second, and for second read first. 



Page 216, in explanation of Plate 8, f. — f. is second branch and s. — s. is first branch 

 of anal vein ; and i. e. is part of first branch of anal vein. 



Page 217, under explanation of Plate 9, line 3, for penus read penis. 



» Mr. Williamson has shown that the shape of the apex of segment 8 of the abdomen 

 is difficult of accurate definition as a distinctive character. (See Williamson, E. B., 

 'Gomphus pallidus and two new related species (Odonata)." In Ent. News, vol. 25, 

 pp. 49-58, pis. 4, 5. February, 1914. See pp. 50 and 58 and pi. 4, fig. 8.) 



