572 



Thorax pale blue and black, lacking the black stripes on the meta- 

 pleiiral sutures, and the femoral black stripes almost wanting or re- 

 duced to short subapical lines. 



Abdomen with the pale and black markings similar to those of 

 the male; anal appendages of the usual type, the ovipositor with pro- 

 styles extending caudad to the apex of the anal appendages. 



Measiirements 



Length, $ 24 mm. 



Length, 9 29 mm. 



Length of abdomen, $ 19 mm. 



Length of abdomen, 5 18-22 mm. 



Length of hind wings, $ 12 mm. 



Length of hind wings, 5 13-16 mm. 



Width of hind wings, $ 2.5 mm. 



"Width of hind wings, 2 2.5-3.5 mm. 



A common species in southern and central Illinois, occurring in 

 the same localities where vcrticalis is abundant. The adults appear 

 usually somewhat later than vcrticalis, and the earliest reared speci- 

 mens in my collection bear the date June 12, 191 5. 



Specimens have been seen from Havana, Peoria, and LTrbana. 



IscHNURA ve;rticaus (Say) 



Nymph. — Color, pale green, buff, or dark brown. 



Head broader than long, subelliptical, the caudo-lateral angles 

 with strong setae ; antennae with the first two segments and the prox- 

 imal third of three dark, the remainder pale; first two segments sub- 

 ec|ual, the third as long as the first two together ; labium, when folded, 

 extending slightly caudad of the procoxae, with four or five mental 

 setae and six lateral setae, the lateral marginal setae of the median 

 lobe six or seven in number. 



Thorax nearly equal in diameter throughout ; front femora with 

 a strong row of setae on the cephalic surface and all the femora with 

 preapical rings of brown ; tibiae with several rows of apical setae, 

 two of which extend far proximad ; wing-cases extending caudad to 

 the fourth abdominal segment. 



Abdomen cylindrical and with feeble lateral keels on segments 

 T-8, the margins and ventral surfaces being thickly studded with short 

 setae; cuticle of the abdomen with small dark spots from which minute 

 setae usually arise, one to each spot; gills (Figs. 62. 65) with long 



