THE CANADIAN FNTOMOLOGIST 22? 



o 



. As in the case of the bog at Field, there were very few dragonflies here 

 but I soon observed A. sitchensis dying and ovipositing as before, and soon 

 afterwards a Soniatochlora was "seen and captured. It was not., however. 

 franklini, but a species which at present has no published name. Somatochlom 

 exuviae were rather common and I obtained a full grown nymph, but for some 

 time I found no trace of Aeshnas. After further search I found an exuvia, 

 but was disappointed in recognizing it as jiincca, a species that is abundant here 

 about the small ponds in the.marsh along the railway track, where I found many 

 of the exuviae. At length, however, I found four small Aeshna exuviae of the 

 penultimate stage, to judge by their wing-length, and one slightly larger exuvia 

 of the final moult. These, which from their small size I had no doubt were 

 sifchcusis, were supplemented by three others on the following day. Males and 

 females are represented by both stages. 



These nymphs look like miniatures of A. intcrnipta or crcuiita, but 

 resemble still more closely that of A. coerulca Strom, wliich was described 

 recently by F. Ris ( Mitteilungen der Schweizerischen Entomologischen 

 Gesellschaft, Bd. XII. pp. 348-354, Taf. XIX, 1916). This was to be expected, 

 as these two species are very nearly related and together form a distinct section 

 of the genus Aeshna. The haunts of coerulca in Switzerland, as described by 

 Ris, are also strikingly similar to those of sitchensis, as indicated by the fol- 

 lowing passages :—"es war an sehr massig ansteigender Talflanke eine kleine, 

 flache, ganz von Ouellen ausgefiillte Mulde, ohne grossere Wasseransammlung, 

 teilweise torfig, hauptsachlich aber iiber schieferigem Geroll mit massenhafter 

 Vegetation von Saxifraga aizoides." (Op. cit., p. 350) ; and again, concerning 

 another locality: "Sie Aug nicht am See selbst. sondern auf quelligem und 

 torfigem Gelande in seiner unmittelbaren Umgebung." 



Aeshna coerulca is a circumpolar species, occurring in . North America 

 as the race septentrionaUs. I took a single specimen of this form at Banff, in 

 1913, flying with sitchensis, and it is very probable that it breeds in the same 

 places as the latter, though apparently very rare here. 



DESCRIPTION OF THE NyMPH. 



Nymph small and rather slender. Head as in jiincea and interntpta, 

 broadest across the middle of the eyes, which are a shade more prominent than 

 in interntpta. Lateral margins of head short, passing through well-rounded 

 angles into the posterior margin, which is straight or feebly excavated when 

 viewed directly from above. M,entum of labium reaching back to middle of 

 mesocoxae, very like that of eremita in form, basal breadth about tliree-fifths 

 of the apical, greatest breadth four-fifths of the length; the sides nearly straight 

 and feebly divergent from base to a point just beyond the middle, distad of 

 which they are strongly arcuate. Middle lobe prominent, narrow and obtus- 

 angulate, resembling that of jnncea closely. Lateral lobes broad, the terminal 

 parts subequal, squarely truncate, outer angle scarcely rounded, inner angle 

 with a minute tooth. Supra-coxal processes rather short and blunt, subequal 

 in length, the posterior slightly the stouter, the interval nearly rectangular. 

 Abdomen broadest at segments 6 and 7, a little slenderer than in interrupfa; 

 lateral spines present on segments 7 to 9 only, those of 7 minute rudiments, 

 those of 8 extending half way to the base of seg. 9, those of 9 as far as the 



