64 CONNECTICUT GEOL. AND NAT. HIST. SURVEY [Bull. 



Connecticut. — West Thompson, 12 July, 1905 (H. L. V.) ; Hamden, 18 

 July, 3 August, 1920; Guilford, 27 July, 1920 (P. G.). 

 New England. — June 17-September 2. 



Enallagma vesperum Calvert ^ 



Transactions of the American Entomological Society, 45: 380: 1919. 



Nymph. — Color green or buff. 



Head : about twice as broad as long, the caudo-lateral angles 

 projecting slightly and with but few spines; first antennal seg- 

 ment dark, remaining ones paler; three mental setae, and five 

 laterals. 



Thorax : femora with preapical brown rings ; . metathoracic 

 wing-cases reaching the middle of the third abdominal segment or 

 beyond. 



Abdomen : with strongly developed lateral keels, the spines 

 grouped conspicuotisly at the apices of the keels, especially on 

 segments 2-6; gills (PI. 11, Fig. 10) lanceolate, frequently greatly 

 widened beyond the middle, usually with two more or less fused 

 cross-bands near the proximal third, and three lighter crescentic 

 ones beyond, which are sometimes wanting; axis dark; median 

 gill without heavy dorsal spines as in signatum, the ventral margin 

 of the lateral gills with a thick row from base to the first cross- 

 band. 



INIeasurements : length, 5.5 mm. ; length of abdomen, 9 mm. ; 

 length of gills, 5.5 mm.; length of metathoracic wing-cases, 4.1 

 mm.; length of median lobe, 1.8 mm.; width of median lobe, 

 .5-1.5 mm. 



Adult, male. — Color lemon-yellow, or very pale blue and black 

 (the majority of the specimens are yellow and the blue tenerals 

 are infrequent). 



Head : yellow and black ; labitmi yellow ; antennae brown and 

 pale, the first and basal two-thirds of the second pale, remainder 

 dark brown ; postclypeus almost entirely black or dark, the black 

 usually enclosing two small yellow spots ; anteclypeus and labrum 

 yellow, the latter with a small dorso-mesal black spot and a lateral 

 one on each side; front above the clypeus nearly to the median 

 ocellus, yellow ; remainder of the front black except a small spot 

 cephalo-ventrad of each lateral ocellus. Postocular spots large, 

 cuneiform, connected with the narrow stripe behind the ocellar 

 area ; occiput and postgenae largely yellow. 



Thorax : yellow and black ; pronotum, with yellow cephalic 

 lobe, a large spot on each median lobe and smaller near the mesal 

 line (four in all); caudal lobe with pale margin; proepimera 

 mostly yellow ; mesothorax with black mid-dorsal stripe, the mar- 

 gins of which often fade into brown ; dark stripe of the meso- 



* pollutum Hagen. 



