200 THE CANADIAN ENTOMOLOGIST 



lobes slenderer than in the other species, the marginal teeth 

 prominent, the end-hook long and slender. Inner hook of outer 

 part twice as long as the row of teeth, which is shorter than usual; 

 lateral setae 3. 



Lateral spines on segments 2- or 3-9, larger than in the 

 other species, those on segment 9, e.g., being about one- 

 fourth the length of the lateral margin of segment 10. Spinules 

 on lateral carinae of segment 9 generally only 6-9, in extreme 

 cases 5 or 11. Styli and apex of ovipositor not reaching the hind 

 margin of segment 10, or the styli barely reaching the margin. 

 The longitudinal series of minute hairs on the ventral margin 

 of the valves is quite near the inner margin of the valves. Gills 

 narrow, the margins being for the greater part of their length 

 nearly straight and subparallel, apices rather broadly rounded, 

 with or without slight indications of a point. Femora with a 

 preapical annulus and the extreme apices dusky; a narrow sub- 

 basal tibial annulus is sometimes present. 



Length of body (without gills) 21-23-5 mm.; labium 3.33- 

 3.8; outer wing-pad 5.2-5.4 mm.; hind femur 5.0-5.5 mm.; gill 

 10.0-10-5 mm.; ovipositor 2 mm. 



Explanation of Plates. 



Plate XIII. Ventral views of labium and thorax, showing their 

 relative positions when the former is closely applied to the ventral 

 surface of the latter. The mental setae are seen through the 

 mentum, as they appear in the transparent exuviae. 



Fig. 1. Lestes congener. Fig. 4. Lestes disjunctus. 



Fig. 2. eurinus. Fig. 5. rectangular is. 



Fig. 3. uncatus. Fig. 6. vigilax. 



Plate XIV. Lateral lobe of labium (figs. 7-1 1) and ventral 

 views of abdominal segment 10 of the female, showing ovipositor, 

 etc. (figs. 12-16). 



