No. 39] ODONATA OF CONNECTICUT: GOMPHIDAE 1 25 



For literature pertaining to the family see : 

 Selys, E. de, and Hagen, H. Monograph des Gomphines, 1858 : 8-460. 



Bulletin de I'Academie royale . . . de Belgique (2) 7 : 530-552 : 1859 ; 



8: 162-208; 1869; 35: '72>'2-'7TA: 1859; 36: 492-531: 1873 1 46: 408- 

 471 : 1878. 

 Needham, J. G. — Canadian Entomologist, 29: 164-168: 1897; 29: 181-186: 

 1897: pi. 7- 



Key to Genera 



Nymphs 



1. Third segment of antennae thin and flat, almost circular in outline 2 

 Third segment of antennae not thin and flat or greatly different 



from the other segments except in length" 3 



2. Abdomen nearly as broad as long, and thin and flat, with promi- 



nent dorsal hooks (PI. iii, Fig. 8) Hagenius, p. 127 



Abdomen not nearly as broad, or thin and flat, and without dorsal 

 hooks or prominences 5 



3. Middle coxae more approximate than the front coxae; proximal 



segment of the palpi not serrate on the mesal margins (PI. v, 

 Fig. 7); terminal segment of the antennae long, recurved ... 



Progomphus, p. 125 

 Middle coxae not more approximate than the front coxae ; proxi- 

 mal segment of the palpi serrate on the mesal margins; terminal 

 segment of the antennae short and not recurved 4 



4. Proximal segment of the labial palpi blunt at apices 



Ophiogomphus, p. 129 

 Proximal segment of the labial palpi with a hook at apex of the 

 proximal segment or the apex decidedly pointed 5 



5. Ninth abdominal segment with an acute dorsal ridge and spine at 



apex ; this segment never as long as wide at base 



Dromogomphus, p. 167 

 Ninth abdominal segment rounded and without a sharp apical spine, 

 if with a dorsal carina, then the segment as long or longer than 

 wide at base Lanthus; Gomphus, pp. 138, 141, 142 



Adults 



1. Anal loop present in the hind wing and composed of more than 



two cells ( PL X, Fig. 2) 2 



Anal loop absent in hind wings; composed of one or two cells (PI. 

 IX, Fig. 3) 3 



2. Triangles of both wings without cross-veins ; length usually less 



than 50 mm Ophiogomphus, p. 129 



Triangles of both wings with a single cross-vein; length 70 mm. 

 or more Hagenius, p. 127 



3. Triangles with cross-veins ; subcostal cross-vein present 



Progomphus, p. 125 

 Triangles without cross-veins ; subcostal cross-vein absent 4 



4. Hind femora with long spines interspersed with shorter ones . . . 



Dromogomphus, p. 167 

 Hind femora naked or with rows of short spines, either uniform 

 in length or gradually increasing in length from base to apex, 



never with long spines and shorter ones between 



Lanthus; Gomphus, pp. 138, 141, 142 



Genus Progomphus Selys^^ 

 Nymphs. — Proximal segment of labial palpus rounded at apex ; 

 third segment of antennae cylindrical, the fourth about as long 



" The third scRment in Ophiogomphus is sliRhtly flattened. 



'^' Erpeto gomphus, including several Southern species, is distinguished mainly by 

 the long, upcurved, contiguous, inferior appendages of the male. 

 '^ Gomphoides Selys. 



