236 CONNECTICUT GEOL. AND NAT. HIST. SURVEY [Bull, 



Neurocordulia yamaskanensis (Provancher) 



Naturaliste Canadienne, 7: 238, 248: 1875. 



Adult, male. — Brown, labrum yellow, front and vertex olive. 



Thorax: brown, pilose; legs brown, the dorsal ridges of the 

 tibiae pale; wings with brown spot at base of the hind wings, 

 not, however, extending beyond the triangle ; front wings chlori- 

 nated as far as the arculus, the first two antenodals showing some 

 infuscation, but without a dark spot reaching the hind margin as 

 in obsoleta; antenodals of the front wing 9 to 11, hind wings 

 usually 6. 



Abdomen: brown, bulbous at base, with pale spots along the 

 sides of segments 5 to 8 inclusive; inferior appendage nearly as 

 long as the superiors, contracted to a blunt point at apex ; superior 

 appendages slender, acute, the tips upturned and in lateral profile 

 with a slight obtuse projection on the ventral surface just beyond 

 the middle. 



Female. — Similar in nearly all points to the male. Vulvar 

 lamina consisting of two small plates with an almost rectangular 

 notch between. 



Measurements: total length, male 52-53, female 52 mm.; 

 length of abdomen, male 35-37, female 37 mm. ; length of hind 

 wings, male 33-35, female 36 mm. ; width of hind wings, male 

 and female, 11 mm. 



This species is similar in nearly all respects to obsoleta of Say 

 but differs mainly in size, greater number of antenodal cross- 

 veins, and amount of infuscation on these. The species has been 

 described in great detail by Hagen (Psyche, 5; pp. 367-369, pi. i, 

 figs. 1-6: 1890). The wings are figured by Williamson in Ent. 

 News, 19: pi. xviii: 1908. 



Connecticut. — Salisbury, 13 June, 1926 (P. G.). 



Genus Williamsonia Davis 



Generally placed in Dorocordulia but separated from that genus 

 by some authorities because of the absence of a 3-celled internal 

 triangle. 



Williamsonia (Dorocordulia) linfncri (Hagen) is the only 

 representative in New England. 



Nymphs. — Unknown. 



Adults. — Sectors of the arculus not united at base; triangle 

 without cross-veins; area between Cuj and M4 not widened at 

 margin of the front wing; wings without dark spots, their bases 

 however, flavescent ; abdomen of female without a long forked 

 process on the venter of segment 8. 



