NO. 2192. DRAOONFLIES, CALIFORNIA AND NEVADA— KENNEDY. 581 



but long hair just above the coxa. Wing pads parallel and reaching 

 almost to the fifth abdominal segment. Legs short but not especially 

 distorted for burrowing; burrowing hooks on fore and middle tibiae. 



Abdomen flat ventrally, convex dorsally and thin at the edges, ovate 

 when viewed from above. This may be broadly ovate in the Uve 

 nymph, which can make itself very flat (thin dorso-ventrally) or nar- 

 rowly ovate in the exuvia, which is convex on both dorsal and ven- 

 tral surfaces. Short lateral spines on segments 7, 8, and 9. Segment 

 10 one-half as long as segment 9 and slightly more than one-third as 

 wide, but one-third longer than the lateral spines of segment 9 between 

 which it Hes. Appendages of segment 10 short, conical, the inferiors 

 twice as long as segment 10, the middle only sUghtly less long, the 

 dorsal paired appendages sUghtly longer than 10, The entire thorax 

 and abdomen granulated except the intereegmental membranes. 

 Postero-dorsal and lateral edges of segments 2-8 with a crowded 

 row of short heavy bristles scattered among which are very long hairs. 

 Segment 1 is one-third as long as segment 2. An impressed hne on 

 each side of the median line of the ventral surface, each hne running 

 out posteriorly at the base of the lateral spine on segment 9. 



The male larvae can be told by the scar on segment 2, the females 

 by the genitalia at the base of segment 9. 



OctogompJius imagoes are close to Gomphus in the venation of the 

 wings and the nymphs are very similar to those of Lanihus. They 

 differ from nymphs of Lanthus alhistylus ^ in greater size, in the nar- 

 rower tliird joint of the antennae, in the narrower head, in having two 

 to four vertical ridges on the postocular areas instead of one large one, 

 in the smaller teeth on the lateral lobe of the labium and that these 

 are larger at the proximal end of the series. (Both have four teeth 

 on the middle lobe.) Legs and thorax and abdomen are similar 

 except that there are lateral hooks on segments 7-9 in Odogomphus, 

 while in Lanthus they occur only on segments 8 and 9. 



15. NOTES ON AESHNA INTERRUPTA NEVADENSIS AND ITS NYMPH. 



Tliis dragonfly, originally named nevadensis by Dr. E. M. Walker, 

 is classed in his recent monograph as a variety of Aeshna inierrupta. 

 Only eight specimens, all males, are recorded. These were collected 

 at Reno, Nevada, by H. K. Morrison, and were deposited in the 

 Museum of Comparative Zoology. 



This Aeshna is an alpine form, I first met it on July 21, when I 

 was chmbing down the thousand-foot hill from Emigrant Gap (CaU- 

 fornia) into Bear Valley. Here, on the fir-covered hillside along the 

 power company's canal, two specimens were catching insects with 

 that peculiarly airy fhght and dextrous turning characteristic of this 

 variety. I was unable to catch either, and decided they were Aeshna 

 interrupta interna, which they resembled in appearance and habits. 



I Collected by E. B. Williamson on Pine Creek, Ashland County, Ohio, June 7, 1915, 



