564 



Head similar to that of the male but lighter in color. 



Thorax buff, and not blackish on the dorsum as in the male; 

 mesostigmal plates as shown in Figure i8i. 



Abdomen : terga 1-4 red ; terga 5-7 red with two black spots on 

 each near the caudal fourth ; terga eight and nine with two longitudinal 

 black stripes extending from the cephalic margins to within a very- 

 short distance of the caudal margins ; tergum ten pale buff ; sterna 

 i-io buff; eighth sternum with a long seta; ovipositor with broad, 

 buff, lateral valves, the ventral margins serrate ; prostyles short, brown, 



Measurejnents 



Length, S 26 mm. 



Length, 5 26 mm. 



Length of abdomen, S 21 mm. 



Length of abdomen, $ 21 mm. 



Length of hind wings, $ 16 mm. 



Length of hind wings, 2 16 mm. 



Width of hind wings, S 3.5 mm. 



Width of hind wings, 2 3.5 mm. 



Adults have been collected at LTrbana during the latter part of 

 May and early part of June, but the species has at no time appeared 

 in great abundance, and attempts to secure the nymphs from this 

 locality have failed. 



Genus Chromagrion Needham 



The nymphs of this genus are characterized by the projecting 

 caudo-lateral angles of the head and the extremely long and slender 

 gills, which are without conspicuous marginal setae. The median lobe 

 of the mentum is provided with mental setae and the proximal seg- 

 ments of the labial palpi have a single sharp fixed hook and a blunt 

 process with teeth at the apex. The lateral keels are not well developed 

 and are without heavy setae. 



The adult is characterized by the absence of postocular spots, by 

 the long, somewhat forcipate, anal appendages of the male, and by 

 the peculiar formation of the pronotum of the female — as shown in 

 Figure 170. The parameres of the male extend to the apex of the 

 ninth sternum. 



The genus is represented in North America by a single species. 



