100 NETJROPTERA OF NORTH AMERICA. 



3. G. boa. 



Erpetogomplms boa Selys ! Addit. Synops. 11, 21 quart. 



Yellow ; head yellow ; thorax yellow, varied with obscure fus- 

 cous ; femora yellow, externally with a fuscous fascia, tibire fus- 

 cous, or yellow, with the outside black, the four anterior tarsi 

 brownish-black; abdomen yellowish; superior appendages inflated 

 at base, an obtuse tooth above; their apex curved inwards, obtuse, 

 villous; the inferior one bifid, shorter; the vulvar lamina excised; 

 wings hyaline ; pterostigma pale fuscous. (From the description 

 of De Selys Longchamps.) Male. 



Length 47 millim. Alar expanse 69 72 millim. 



Hob. Vera Cruz, Mexico. 



4. G. cophias! 



Erpetogomphus cophias Selys ! Monog. Gomph. 72, 17 ; pi. iv, fig. '6. 

 Selys, Addit. Synops. 11, 21 quint. 



Yellow; head yellow, between the ocelli fuscous; thorax yellow, 

 dorsuni having an obsolete, humeral, rufous stripe ; abdomen yel- 

 low, segments 4 9 each side blackish-fuscous ; segment 10 with 

 two basal, black spots ; femora yellow, with a black fascia exter- 

 nally, tibise and tarsi black ; superior appendages inflated at base, 

 with a basal tooth beneath; at the apex they are obtuse; the infe- 

 rior one bifid, shorter ; wings hyaline, pterostigma pale fuscous ; 

 vulvar lamina short, each side orbicular. 



Length 47 millim. Alar expanse 64 millim. Pterostigma 3 

 millim. 



Hob. Mexico; Trojes del Oro (Saussure). 



* 



5. G. elaps! 



Erpetogomphus elaps Selys ! Monog. Gomph. 70, 16 ; pi. iv, fig. 4. Selys, 

 Addit. Synops. 12, 21 sext. 



Yellow; head yellow, between the ocelli fuscous; thorax yellow, 

 dorsum each side with an obsolete, humeral, rufous vestige ; femora 

 yellow, externally with a black fascia, tibiffi and tarsi black ; abdo- 

 men slender, yellowish, before the apex dilated, the second segment 

 each side, lineated with black, and with a trilobed, dorsal, yellow 

 spot ; segments 3 6 blackish, with a yellow, basal ring, or yellow 

 with an apical black ring (teneral), segment 7 yellow, or sometimes 

 fuscous behind, segments 8 10 fuscous, obscurely varied with 

 black ; superior appendages contiguous, not inflated at base, the 



