528 



)\Ieasurements 



Length, $ 33-35 mm. 



Length, 5 34 mm. 



Length of abdomen, S 26 mm. 



Length of abdomen, 2 26 mm. 



Length of hind wings, $ 19 mm. 



Length of hind wings, $ 21 mm. 



Width of hind wings, $ 4 mm. 



Width of hind wings, $ 4-4.5 mm. 



This species is closely related to caruncluatum, chile, doublcdayi, 

 and cyathigerum. The adult male is easily distinguished from those 

 species by means of the anal appendages; the female, less easily, by 

 means of the mesostigmal plates. 



Illinois is within the range of the species and it probably occurs 

 within the state although there seems to be no record of its presence. 



A large number of adults of both sexes have been examined, all 

 in the collection of Mr. E. B. Williamson. 



Enallagma carunculatum Morse 



Nymph. — Color, green or buff. 



Head about twice as broad as long, the caudo-lateral margins not 

 projecting strongly, but with a few strong setae ; antennae with the 

 third segment longest, the second longer than the first, the first two 

 and the proximal portion of the third darker than the rest ; mental setae 

 of the median lobe three, and sometimes a small fourth on each side; 

 lateral setae six ; marginal setae of the median lobe eight or nine on 

 each side ; labium extending caudad between the first and second pair 

 of coxae. 



Thorax : legs pale, the femora with very faint or no preapical 

 rings and distinct rows of moderately heavy setae ; tibiae and tarsi 

 with the usual apical scales and ventral setae ; metathoracic wing-cases 

 extending about to the middle of the fourth abdominal segment. 



Abdomen with well-developed lateral keels, the keel of the first 

 segment with three or four setae; the second, with eight to twelve; 

 third, with about eleven; fourth, with thirteen to fifteen; fifth, eighteen 

 to twenty; sixth, eighteen to twenty; seventh, twelve to fourteen; and 

 the eighth with about fourteen ; on the fifth and sixth keels the setae 

 are bunched at the apex, with sometimes as many as three together; 

 venter of the abdomen entirely without small setae on the cephalic seg- 

 ments, but usually with long hair-like setae on the dorsum of segments 



