534 



A common species at Urbana. It was not taken at Havana, where 

 carunculatum was abundant, nor at Lake Villa, where both caruncu- 

 latum and hageni were common. The females of these closely allied 

 species have been determined from material collected in the above 

 localities. A study has also been made of specimens taken in copula, 

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



The imago emerges at Urbana as early as June 13 and apparentlv 

 continues to emerge throughout the season. Nymphs taken late in 

 July emerged shortly after, and another lot, collected at Lexington, 

 Ky.. emerged as late as August 18, 1915. There is a possibility that 

 the species has two broods a year. 



Enaixagma cyathigerum (Charpentier) 



Nymph. — Color, buff. 



Head elliptical, the caudo-lateral angles rounded and sparsely 

 setose; antennae of the usual form, the second segment slightly longer 

 than the first ; labium broad, and extending caudad to the mesocoxae ; 

 mental setae four, the proximal seta of both rows more than half as 

 long as the remaining ones ; lateral setae five or six ; marginal setae 

 of the median lobe four or five. 



Thorax : femora without conspicuous rows of small setae ; wing- 

 cases extending caudad to the middle of the third abdominal segment. 



Abdomen with distinct lateral keels all of which are setose in- 

 cluding those of the first segment; the size of the setae gradually 

 increases caudad, and on each lateral surface of the ninth segment 

 there is a row of setae in line with the lateral keels with two or 

 more setae grouped together at the caudal end of the row; gills (Fig. 

 71 ) clear and without cuticular pigmentation though reported by 

 Lucas ('00: 103) to have one or more narrow cross-bands beyond 

 the middle ; dorsal and lateral gills with closely placed marginal setae 

 which extend more than half-way from the bases to the apices of the 

 gills ; tracheal branches few in number and usually larger than are 

 found in civile or carunculatum; ovipositor of the female extending 

 caudad to the caudal margin of the tenth abdominal segment. 



Measurements 



Length 14 mm. 



Length of abdomen 9 mm. 



Length of gills 5 mm. 



Width of gills 1.5 mm. 



Length of metathoracic wing-eases. . . .4 mm. 



Length of median lobe 2.5 mm. 



Width of median lobe 75-2 mm. 



