DIPLAX. 173 



are narrower, and the basal spot smaller. (From the description 

 of De Selys Longchamps.) 



Length 40 millim. Alar expanse 66 millim. 



Hab. Island of Martinique. 



7. M. longipennis! 



Libellula longipennis Burm. Handb. II, 850, 12. Libellula socia Ramb. ! 

 Neuropt. 96, 94. Libellula truncatula Ramb. Neuropt. 95, 92? 



Fnscous ; mouth and front yellowish-white ; vertex, and front 

 superiorly, chalybeous ; thorax fuscous, clothed with luteous-hairs, 

 dorsum each side with a streak, and a transverse line at the wings, 

 yellow; sides yellow, with three oblique, fuscous lines; abdomen 

 triquetral, short, sensibly attenuated; of the female, broader at 

 the apex, yellowish, dorsum with three broad, fuscous stripes, con- 

 fluent towards the apex; the last segment extremely short ; append- 

 ages black; abdomen of the adnlt male (more rarely of the female), 

 pruinose ; feet black ; wings hyaline, veins black, the base flaves- 

 cent ; of the adult male often dusky towards the apex ; posterior 

 wings of the male, with a double fuscous streak at base ; wings of 

 the female hardly flavescent, with no basal streaks ; pterostigma 

 fulvous ; membranule black ; six antecubitftls ; six postcubitals ; 

 three discoidal areolets. 



Length 35 — 44 millim. Alar expanse 59 — 10 millim. Ptero- 

 stigma 3 — 4 millim. 



Hab. Maryland ; New York ; Illinois ; Savannah, Dalton, 

 Georgia; Florida; New Orleans, Louisiana; Pecos River, West- 

 ern Texas (Capt. Pope) ; North California ; Matamoras, Mexico. 

 A common species. 



Specimens from Western Texas have the thorax and abdomen 

 almost entirely brassy-black ; but they are not different from the 

 others. 



A male from California has the thorax and abdomen very prui- 

 nose, the extreme base of the wings only is flavescent, and the 

 fuscous streaks are almost absent. 



DIPLAX Charp. 



Eyes connected in a short space ; posterior lobe of the prothorax 

 large, broad, bilobed ; abdomen a little shorter than the wings, 

 slender triquetral, the base compressed ; feet long, slender ; the 



