22 DRAGONFLIES OF OHIO. 



Metallic green, with the last three abdominal joints 

 blackish. The markings of yellow or bluish white are 

 as follows: male — anteclypeus, lips, genae, rear of 

 head, under parts and sides of thorax below% an exceed- 

 ingly narrow stripe on the carina and humeral suture, 

 two stripes on the femora, most of the tibiae and the 

 pleurae of the abdominal segments; there are very 

 narrow basal rings on 3-7. The antennae, tarsi and 

 stripes on tibiae and femora are black. The ptero- 

 stigma is dark brown covering two to three cells. The 

 female differs in having more black upon the legs, the 

 humeral and carinal stripes wider. 



The male abdominal appendages are black ; the 

 superiors are forcipate with a few spines on the outer 

 curve, within a stout acute tooth precedes the usual 

 blade which is narrow, the edge curved and serrate. 

 The inferiors are slender and strongly bent inwards at 

 apex. The anal appendages of the female are slender, 

 rather long and blackish in some examples, light in 

 others ; the valves are narrow and black except on the 

 upper border. 



This beautiful species is quite as active and wary 

 as vigilax, which it closely resembles, it is easily 

 separated however ; the males by their peculiar in- 

 ferior appendages, bright yellow sides of thorax and 

 absence of humeral strips ; the female by the yellow 

 rear of the head, bright yellow on sides of thorax, 

 darker valves and pterostigma and the narrower 

 humeral stripes (sometimes wanting as in the male). 



It has been taken only in northern localities. 



ARGIA, Rambur. 



The species of this genus differ only slightly from 

 those of other genera following, yet they have a "person- 

 ality" that no observer can long fail to appreciate. They 

 prefer the brook-sides and some of the siDecies rarely 

 wander to other localities ; the nymphs live Din the 



