514 



Thorax blue or brown and black ; caudal and cephalic lobes of the 

 pronotum with more or less blue or brown; mesostigmal plates (Fig. 

 140) without projections on the caudal margins; mesopleural stripe of 

 black, somewhat narrower than that of the male, separating more dis- 

 tinctly from the suture at the caudal third, the ventral branch fre- 

 quently stopping short of the caudal margin of the sclerite ; legs paler 

 than those of the male, the femora usually with two dark stripes one 

 on each side of the carina, the remainder pale blue or brown ; tibiae 

 with a black ventral stripe between the rows of setae which frequently 

 includes one of the rows ; tarsi often with the proximal segments pale. 



Abdomen : lateral surfaces, apical ring, and narrow mesal lines of 

 the first tergum pale, the black confined to two dorsal basal spots ; sec- 

 ond tergum with broad lateral blue stripes and a dorsal stripe greatly 

 contracted and then widened again shortly before the apex, the black 

 limited to a narrow apical ring and a dorso-lateral stripe on each side ; 

 segments 3-7 as in the male with the exception of a narrower mid- 

 dorsal pale line ; tergum nine black with a paler narrow apical line, the 

 tenth yellowish or blue, with a narrow basal ring, the segment usually 

 dark below; anal appendages of the usual type, the superiors black or 

 dark, the inferiors slightly paler in color; ovipositor, except the ex- 

 treme tip and the prostyles, dark brown or black. 



Measurements 



Length, $ 34-37 mm. 



Length, 2 35-37 mm. 



Length of abdomen, $ 26-30 mm. 



Length of abdomen, 2 28 mm. 



Length of hind wings, $ 20-22 mm. 



Length of hind wings, 2 24 mm. 



Width of hind wings, $ 4.5 mm. 



Width of hind wings, 2 5 mm. 



The nymphs of this species have been taken beneath rocks in 

 swift currents. A single specimen has been reared and a comparison 

 of the nymph with the nymph of apicalis shows them to be almost 

 identical. Needham ('03) separates the two species on the character 

 of the lateral setae, but there is so much variation in apicalis that the 

 character seems without value. 



The adults are common throughout the state and may be found 

 at almost any point along the banks of clear, swift streams. 



