416 THE CANADIAN ENTOMOLOGIST 



of seg. 8 not declined, directed straight caudad at 



apex intacta Hag. 



DD. Spinules on inner margin of lateral lobes of labium 

 mostly single; lateral setae 11 ; dorsal of seg. 8 gener- 

 ally somewhat declined, the tip sometimes resting 



on dorsum of seg 9* glacialis Hag. 



CC. Dorsal hook of seg. 7 shorter than the mid-dorsal length 

 of the segment, that of seg. 8 projecting barely over 

 the base of seg. 9, lateral spines of seg. 8 slightly 

 convergent, their outer margins continuing the general 

 curve of the abdominal margin; lateral spines of seg. 

 9 not reaching beyond tips of lateral 



appendages proxima Calvert. 



AA. Abdominal segs. 7 and 8 without dorsal hooks, venter of 

 abdomen with 3 conspicuous longitudinal dark bands (rarely 

 inconspicuous). 



E. Length less than 18 mm.; lateral spines of seg. 8 

 two-fifths to one-half as long as the lateral margin 

 of the segment (not including spine) ; dorsal hooks 

 absent or vestigial ones present on some of the 



segments hudsonica Selys. 



EE. Length more than 18 mm.; lateral spines of seg. 

 8 one-sixth to one-fourth as long as the lateral 

 margin of the segment; dorsal hooks 

 absent borealis Hag. 



Leucorrhinia borealis Hagen. 



Nymph. — Eyes less prominent than in the other North Ameri- 

 can species of Leucorrhinia, the width of the head across the eyes 

 being somewhat less than twice the length (not including labium) ; 

 postero-lateral surfaces broadly rounded with numerous coarse 

 hairs. Mentum of labium of the usual size and form, being sub- 

 triangular, nearly as broad as long; the median lobe rather bluntly 

 obtusangulate; lateral lobes with inner margins feebly and broadly 

 crenated, the marginal spines short, single, or with a second vestigial 

 spinule; posterior margin with a few short scattered spinules or 

 almost devoid of these; mental setae 13, occasionally 14, the third 

 *Vidc Necdham, Bull, 47, N. Y. State Mus., p. 519, 1901. 



