Vol. XLVI. LONDON, NOVEMBER, 1914 No. 11 



NEW AND LITTLE KNOWN NYMPHS OF CANADIAN 



ODONATA. 



BY E. M. WALKER, TORONTO. 



( Continued from p. 357.) 



yEshna tuberculifera Walk. 



This rare species was quite common at Lonely Lake, Vancouver 

 Island, a forest pond about two miles from the Dominion Biological 

 Station, Departure Bay. I obtained two mature nymphs, both of 

 which were successfully reared, yielding a specimen of both sexes. 

 Numerous exuviae were also obtained. They were found in marshy 

 coves, thickly grown up with reeds in water 12-20 inches deep, the 

 conditions of environment being of the usual type that is character- 

 istic of this genus. Six other species of ^Eshna were taken at the 

 same spot. 



Nymph (pi. XXV, figs. 1-3) .—The nymph is long and slender and 

 is remarkable for the length of the labium, which closely resembles 

 that of Anax Junius in both form and size. When closely applied 

 to the ventral surface of the thorax, the hinge reaches the level of 

 the hind coxae, and this feature alone will serve to distinguish it 

 from all other North American species of ^Eshna, in none of which 

 the labium reaches back more than half way between the middle 

 and hind coxae. The length of the mentum slightly exceeds that 

 of the hind femora, while in all other species the reverse is the case. 



Eyes slightly less prominent antero-laterally than in other 

 species of the clepsydra groups, with a rather long antero-posterior 

 diameter. Lateral margins of head nearly straight, passing into the 

 straight or sligh tly concave posterior margin by well rounded postero- 

 lateral angles. Mentum of labium very long, the breadth at the base 

 about half that at apex, which is slightly more than half the length; 

 sides in proximal half straight and very slightly divergent, thence 

 gradually curving outwards, the distal third moderately arcuate. 

 Median lobe very broadly obtusangulate; lateral lobes with mar- 



