GOMPHUS. 101 



apex obtuse, subincurved ; the inferior one bifid, one-half shorter 

 than the superior ; wings hyaline, pterostigma fuscous or fulvous. 

 Male. 



Twelve antecubitals ; 8 9 postcubitals ; two discoidal areolets. 



Length 41 millim. Alar expanse 54 millim. Pterostigma 3 

 raillim. 



Hob. Atlihuazan, Mexico (Saussure). 



6., G. crotalinus ! 



Erpetogompkus crotalinus Hag.! Monog. Gomph. 72, 18 ; pi. iv, fig. 5. 

 Selys, Synops. 21, 21. Ophiogomphus menetriesii Selys! Synops. 20, 

 20. 



Greenish-yellow; head and thorax greenish-yellow; feet yellow, 

 exteriorly lineated with black, tarsi black ; abdomen slender, be- 

 fore the apex dilated, greenish-yellow, with a black stripe each 

 side ; superior appendages straight, contiguous, inflated at base, 

 the apex acute ; the inferior one bifid, the apex incurved, acute ; 

 vulvar lamina excised; wings hyaline, pterostigma yellow, sur- 

 rounded by black nervures. 



Eleven antecubitals ; 8 9 -postcubitals ; two discoidal areolets. 



Length 45 49 millim. Alar expanse 66 millim. Pterostigma 

 3J millim. 



Hob. Mexico; Brazil. 



G. menetriesii, from Brazil, very likely, does not differ from this 

 species ; but the typical specimen being destroyed, other speci- 

 mens are to be observed. 



Subgenus Opliiogomplius SELYS. 



7. G. colubrlnus ! 



Ophiogomphus colubrinus Selys! Monog. Gomph. 76, 19; pi. v, fig. 1. 

 Selys, Synops. 21, 22. 



Greenish-yellow ; head yellow, in front with four black lines, 

 labium black in the middle ; thorax greenish-yellow, a middle 

 stripe, and another each side, lateral, narrow, fuscous ; sides, each 

 with three narrow black lines ; feet yellow, the posterior femora 

 exteriorly fuscous, tibia3 black with an external yellow line ; abdo- 

 men cylindrical, before the apex dilated, the dorsum black, seg- 

 ments 3^ 7 with a basal yellow stripe, the rest with a yellow spot ; 

 superior appendages yellow, short, trigonal, subincurved ; the in- 



