66 MARINE AND FISHERIES 



5 GEORGE v., A. 1915 

 12. Nehalennia gracilis Morse. 



Very abundant on all sphagnum bogs bordering lakes and ponds; the most 

 characteristic damsel-fly of such stations. It also occurs in smaller numbers in 

 open marshes. It was first noticed on June 18, 1907, and was found in abundance 

 throughout July. In 1912 it was still common on August 6, but had about disap- 

 peared by Aug. 25. Several imagos emerged in the laboratory during July. 



The nymphs are found in floating sphagnum bogs and are somewhat diflicult 

 to detect. I have compared them carefully with nymphs of N. irene from Toronto 

 and the only differences that I can find are the smaller size, less spinulose hind 

 margin of the head and entire absence of spots on the gills. It is not improbable 

 that none of these characters are constant as I had but few specimens of either 

 species for comparison. 



In N. gracilis the convex posterior margin of the head has only 4 to 6 slender 

 inconspicuous, colourless spinules; in N. irene there are a dozen or more spinules 

 which are somewhat coarser and blackish at base (Figs. 2, 3). Gills very slender, 

 widest in the distal third, tapering somewhat more gradually than in N. irene, 

 without any indication of spots. (Pi. Ill, Fig. 1). 



Length of body 8-25-9; gills 3-3-75 additional; hind wing 2-2-2-7; hind 

 femur 2-2-33; width of head 2-33-2-4. 



13. Enallagma cyathigerum (Charpentier) Selys. 



A single male was taken from an open marsh on June 21, 1907. 



This is the form described by Hagen as E. annexum ('61). I have stated else- 

 where (Walker, '12b) my belief that this form and the following are but variations 

 of the same species, but I find on further study that this conclusion was reached 

 too hastily; the two forms are distinct species. 



14. Enallagma calverti Morse. 



In 1907 only one specimen of this form was taken, on June 16, but in 1912 it 

 was found in considerable numbers early in the season but had seemingly disap- 

 peared before the middle of June. Fully matured imagos were found in the marsh 

 at the outer end of Galbraith Lake on June 1, many of them flying in pairs. The 

 season for transformation was not yet over, however, for several full-grown nymphs 

 were found, four of these emerging on June 3 and 4. Mr. Wodehouse also took a 

 full-grown nymph at Victoria Harbour on June 1. 



The nymph (PL III, Figs. 4, 5) is very similar in form to that of E. hageni,hut is 

 considerably larger with much darker gills. Eyes as in hageni, less prominent than 

 in E. signatum and pollutum, the curve of the posterior median excavation of the head 

 somewhat more flattened than that of the rather strongly convex margins on each 

 side, the latter with a dozen or more spinules. Labium with 4 mental setae and 6 

 (occasionally 5) lateral setae; end-hook of lateral lobe preceded by 3 teeth of mod- 

 erate size, which are preceded by 3 or 4 smaller, somewhat incurved, denticles. 

 Gills lanceolate, widest a little beyond the middle, ventral margin straight at base 

 dorsal margin convexly curved, apices bluntly pointed with convexly curved mar- 



