65 



The nymph has been l)red l)y Calvert, and images, nymphs^ 

 and exnviae were collected by Mr. Needham — all three at the 

 same time and place — near Ithaca, N. Y., in June. Hagen's 

 nymph No. 19, from Michigan, is probably this species. 



The nymph measures 34 mm.; abdomen, 22 mm.; width of 

 head 5.5 mm., of abdomen 7 mm. 



Body elongate, nearly smooth. Antenuce a little more 

 approximated than in related genera, the 3d segment more 

 upcurved at the tip. Labium moderate, mentum slightly 

 widened all the way to its apex; median lobe a little concave, 

 with minute median tooth and a sparse fringe of flat hairs 

 either side of the tooth; lateral lobes short and stout, the 

 apex incurved in a stout hook which considerably exceeds the 

 8 truncate teeth of the inner margin. Tibial ))urrowing hooks 

 strong. 



Abdomen cylindric, becoming sharply triquetral in cross- 

 section posteriorly. Dorsal hooks on segments 2 to 9, on 2 

 rudimentary, but becoming well developed posteriorly, and on 9 

 straight, almost equaling the lateral spines and confluent ante- 

 riorly with the sharp mid-dorsal ridge. Lateral spines on seg- 

 ments 6 to 9 increasing in size posteriorly. Appendages a little 

 longer than the 10th segment, their apices bent a little so as 

 to be divergent; laterals a little shorter than the others. 



VIIL GoMPHus Leach. 



The nymphs of this large and difficult genus represent the 

 typical and most abundant form of the family. The wing-pads 

 are not divergent, as in Proc/onqj/ius, HerpefogompliKS, and Dias- 

 tatomma, nor the third antennal joint subcircular, as in Hage- 

 nius and Lanfhus; nor are the abdominal segments armed 

 with spinose dorsal hooks, as in Dnnnogomphus. Their habits 

 are very similar to those of the rest of the family, with the 

 exception of Hagenhis, as described fully under the family 

 heading. Observations by Mr. Needham at Ithaca and by Mr. 

 Hart at Havana indicate a nymphal life of more than one 



