496 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. 52. 



apex of segment 8. Male with segment 10 terminating dorsallyin a 

 high narrow fork. Shaft of penis without a longitudinal row of spines ; 

 penultimate joint of penis without the pair of heavy spines found in 

 Ceratura, Anomalagrion, and Ischnura (see figs. 85 and 92) ; ultimate 

 lobe terminating in a fleshy fork, the branches of which cm*ve dorsad 

 and caudad, tapering regularly to acute points. 



Color blue and black with blue postocular spots, the dorsum of the 

 thorax sohd black, the dorsum of the abdomen black except a blue 

 dorsal spot on segments 7-9. 



This genus is erected to contain Ischnura denticollis (Burmeister) 

 and a new species almost identical in structure and color. The vena- 

 tion (figs. 86-87) is apparently like that of Isclmura but these species 

 differ from the American species of Ischnura in having the anterior 

 surface of the thorax sohd black. In the structure of the penis they 

 lack the pah* of erect spines on the penultimate segment, which is 

 characteristic of the penis of Ceratura capriola (Hagen) (fig. 82), 

 Anomalagrion liastatum (Say) and Ischnura pumilio (Charp.) which 

 are the type-species of their respective genera. In Ischnura (see figs. 

 70-81), I have examined over 20 species, including all the American 

 species and find the penis to possess always the pair of erect spines 

 on the penultimate segment, excepting one exotic species (elongata 

 Martin), very evidently not an Ischnura. 



The species of Nehalennia have been confused with Ischnura, deri- 

 ticollis ha\'ing been placed in that genus by Kirby,' but, as seen by the 

 figures 83-84, the Nehalennia penis is very different in sti-ucture. 

 Also the female is without a spine on segment 8. 



I feel some trepidation in using the penis as a generic character of 

 so much importance, as little is known concerning its value. 



Type of the genus. — Ischnura denticollis (Bm-meister).^ 



The name proposed is suggested by the black dorsum of the abdo- 

 men ; KtKaLvos = black; ovpa = tail. 



6. A NEW SPECIES OF CELAENURA, WITH NOTES ON C. DENTICOLLIS 

 AND ITS NYMPH. 



In May, 1914, I found among some specimens of Celaenura denti- 

 collis, which were collected on Sharon Pond a mile west of Stanford 

 University campus, a single male of coloration similar to denticollis 

 but with very different appendages. Though I collected some hun- 

 dreds of denticollis in various parts of California and Nevada during 

 1915 and 1916, only thi'ee more specimens of this new species were 

 taken. These were caught on Coyote Creek, in the city of San Jose, 



1 Kirby, W. F. A Synonymic Catalogue of Neuroptera Odonata, or Dragonflies, 1890, p. 147. 



2 It is possible that the type, a female in the museum of HaJle, may be the female of the species we 

 now know as damula. The female of damula has been discovered recently and has a prothorax very 

 similar to that figiu-ed by Calvert for the type-specimen of denticollis, in Halle (Trans. Amer. Ent. Soc, 

 vol. 2i, 1898, p. 38). 



