1908] The Dragoxflies of the Ottawa District. 61 



Ottawa. July 14tli and 18th, 1899, 2 females (Gibson); 

 Clark's Bush, July 16th, 1907, 1 male (Letourneau). 



Wings hyaline or in the so-called variety assimilatum (Uhler) 

 more or less flavescent; legs black; superior appendages of male 

 with a prominent inferior tooth; vulvar lamina of female 

 cleft in the middle ; genital hamule of male (ventral surface 

 of seg. 2) of the fonn shewn in figure. 



An exceedingly abundant species, flying from early July 

 until November. Young individuals are yellowish, but later 

 become red. 



47. Sympetrum obtrusum (Hagen), Kirby. Fig. 26. 

 Ottawa, July 16th and 30th, 1907, 2 females (Gibson); 



August 9th, 1907, 1 male (Letourneau): 1 male, 1 female 

 (Harrington). 



Another very common Sympetrum which apparently has 

 not yet become quite distinct from ruhicunduhini. Generally, 

 however, there is no difficulty in separating the males by the 

 form of the genital hamules. The face too. is paler than in 

 riibiciuiduliim, being almost as white as that of a Leucorhinia; 

 and the size usually a little smaller. 



Genus Erythemis, Hagen. 



48. Erythemis simplicicollis (Say). Calvert. 

 Ottawa, July 19th, 1907, 1 male, 1 female (Young). 



A beautiful grass-green dragonfly about 4.3 mm. long, with- 

 out thoracic markings, or with only the sutures black; the 

 abdomen mostly brown or black in its apical half. Wings 

 hyaline, pterostigma elongate, pale brown. Old males are pale 

 greyish blue, the thorax and abdomen becoming entirely prui- 

 nose. 



This species, though common in southern Ontario, will 

 proViably not be found in large numbers at Ottawa. It frequents 

 marshy lakes and swamps. 



Genus Libellula, Linne. 



This genus consists of large stout-bodied forms in most of 

 Avhich the wings are m.ore or less conspicuouslv spotted or 

 banded. The triangle of the fore wings is narrow and very much 

 elongated posteriorly, and is generally crossed by two or more 

 parallel veins. The sexes are alike in wing pattern and the 

 male is without the ventral hooks on the first abdominal .segment, 

 which characterize the next genus. 



Some of the species are among our inost familiar dragonflies 

 and may be seen flitting about every stagnant pond or ditch in 

 midsummer. 



