20 The Ottawa Naturalist [April 



is much smaller than the first, the inferior appendages are some- 

 what more dilated apically, and the antehumeral band is broader. 

 It is also larger than disjunctus, as seen from the following 

 measurements: L. disjunctus, length, oi abdomen, male 27-30.5 

 mm., female 26-29 mm. L. jorcipatus, length of abdomen, 

 male, 30-35 mm., female, 28-34 mm. (Calvert). 



Two other Lestes, L. rectangularis and L. vigilax, are likely 

 to be met with about Ottawa, and a third, L. in(equalis,niay 

 perhaps occur there. L. rectangularis, which is common in 

 Algonquin Park and generally distributed throughout most of 

 the Province, may be known in the male sex by the exceed- 

 ingly long attenuated abdomen, the brown color and form of the 

 appendages. L. vigilax is a large slender metallic green species, 

 the male of which has inferior appendages very straight and 

 slender. The superiors are less curved than irr our other species, 

 and have but a single basal tooth. 



Genus Argia, Rambur. 



Of the three species of Argia known from Ontario two are 

 found at Ottawa. In these the spines of the tibiae are about 

 twice as long as the spaces between them. In the remiaining 

 genera they are always shorter than this, generally shorter 

 than the spaces between them. 



7. Argia putrida (Hagen), Selys. 



Ottawa, 4 males, 5 females (Fletcher, Harrington, Taylor) ; 

 July 21st, 1907, 1 male (Young); Meach Lake, July 21st, 1907, 

 1 male, 1 female (Gibson); Sand Hill, Rideau River, Juty 2nd, 

 1906 (Fletcher). 



On account of its large size this species is not likely to be 

 mistaken for any other member of our fauna, unless it be a 

 Lestes, from which it differs in the characters given. The 

 males are at once known from those of Lestes by the appendages, 

 which are very short and not forcipate as in tha^t genus. 



.4. putrida is at first a dull brown or clay-colored insect, 

 but the old males are quite conspicuous on accoiirit of the 

 bluish-white dust which covers most of the body. 



Unlike our other Agrionidae, which prefer quiet marshy 

 haunts, putrida inhabits exposed rocky shores, piers, etc., often 

 where there is considerable wave action. It is probably common 

 about all the larger bodies of water in the Ottawa district. 



8. Argia violacka (Hagen), Selys. 



Ottawa, 3 males, 1 female (Tavlor) ; Meach Lake, Julv 21st, 

 1907, 1 male, 1 female (Gibson);' HuU, July 13th, Mth, 1907, 

 9 males, 3 females (Gibson, Letourneau). 



Apparently a common species in the Ottawa district, 



