138 CONNECTICUT GEOL. AND NAT. HIST. SURVEY [Bull. 



Ophiogomphus rupinsulensis (Walsh) 



Proceedings of the Academy of Natural Sciences of Philadelphia, 388: 

 1862. 



Adult, male. — Color yellow or greenish and black. 



Head : yellow except ocellar area, which is dark brown ; labium 

 pale. 



Thorax : pale with exception of a narrow dark stripe on the 

 mesopleural suture and another above on the anepisternum, the 

 latter not reaching the wing bases ; femora light at base, darker 

 at tips, and with short spines below, not in rows at bases ; tibiae 

 brown, lighter above, with a double row of spines beneath, and 

 two spinigerous ridges above ; tarsi and claw black ; wings clear. 



Abdomen : yellow, obscurely marked with black near the apices 

 and along the sides of the terga; terga 8 and 9 much expanded 

 and in some specimens 5 to 6 times as wide as 3 and 4; anal 

 appendages as in Fig. 14, No. 2, yellow ; superior anal appendages 

 spinose beneath. 



Female. — Color similar to the male. 



Head : occiput with two widely separated spines on the dorsal 

 surface (Fig. 14, No. 8) and two very heavy projections below 

 the occipital ridge on each side; vulvar lamina a Httle more than 

 three-fourths as long as the ninth sternum, and with a median cleft 

 about half their length. 



Measurements : total length, male 50-52, female 45-47 mm. ; 

 length of abdomen, male 35-36, female 32-34 mm. ; length of 

 hind wings, male 28-30, female 29-30 mm. ; width of hind wings, 

 male and female, 9 mm. 



Described from specimens in collection of P. P. Calvert, Phila- 

 delphia, Pa. 



Connecticut. — Salisbury, 13 June, 1926 (P. G.). 



New England. — June 13-August. 



Genus Lanthus Needham 



Nymphs.- — Proximal segment of labial palpus not truncate ; 

 third antennal segment flattened conspicuously ; middle coxae not 

 more approximate than the front; no dorsal projections on abdo- 

 men ; ninth segment without an acute spine at apex. 



Adults. — Subcostal vein absent ; triangles without cross-veins ; 

 anal loop indistinct ; vertex without acute ridge between compound 

 eyes; dorsum of thorax brown; hind femora extending beyond 

 the caudal margin of the first abdominal segment; inferior anal 

 appendages of the male with widely divaricate arms. 



Adults of Lanthus are so closely allied to Gomphus species that 

 they are separated only with difficulty. The nymphs, however, 

 are fairly distinct and the genus is retained mainly on this account. 



For key to species see combined key p. 142 of Gomphus and 

 Lanthus. 



