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



2. Wings with large well-defined spots of brown; cells of anal loop 



18-20 in number ; more than 20 cells between M2 and Rs beyond 



the oblique vein (PI. xiir, Fig. i) Celithemis, p. 284 



Wings without well-defined spots, if with brown areas, the latter 

 more or less diffused over the base of the wing, or sometimes 

 with small, nearly black areas at extreme base ; cells of the anal 

 loop 8-13 in number; cells between M2 and R beyond the olDlique 

 vein less than 20 3 



3. Face white; predominant color of thorax and abdomen black; 



(tenerals have the thorax dark brown and abdomen black) ; base 

 of hind wings with a small triangle of black (PI. xv, Fig. 4).. 



Leucorrhinia, p. 278 

 Face buff or yellow ; predominant color of thorax and abdomen 

 brown and red, or olive and buff, never black; base of hind 

 wings without a small triangle of black (PI. xiv, Fig. 3) .... 



Sympetrum, p. 266 



4. Spines of hind femora suddenly enlarged near the apex, the last 



3 or 4 much longer than the proximal ones and farther apart; 

 antenodal cross-veins of the front wing 10 or more (PI. xx, b) 



Erythemis, p. 264 

 Spines of hind femora gradually lengthened from base to tip, the 

 last 3 or 4 not greatly longer than those immediately proximad; 

 antenodal cross-veins of front wings usually less than 10 5 



5. Width of the venter of abdominal segment 5, 2 mm. or more ; 



stigma with i or no cross-veins behind it (PI. xiv, Fig. i) .. 



Pachydiplax, p. 277 

 Width of the venter of abdominal segment .=; less than 2 mm. ; 

 stigma with two or more cross-veins behind it (PI. xiii, Fig. 3) 



Erythrodiplax, p. 262 



Genus Erythrodiplax Brauer 



Nymphs. — Labium with setif orm movable hooks ; 9 lateral and 

 13 mental setae; abdomen without dorsal hooks, but with lateral 

 spines on segments 8 and 9; superior anal appendages not 

 decurved. 



Adults. — Wings with less than 10 antenodal cross-veins, usually 

 7-10; distal and proximal ends of the stigma parallel, more than 

 three times as long as wide, and supported by two to three cross- 

 veins (usually two) ; triangle 3-sided, considerably farther distad 

 in the front than in the hind; M, not sinuate; Cu^ not arising 

 from the caudal point of the triangle in the hind wings; subtri- 

 angle absent ; hind margin of the pronotum bilobed and with long 

 marginal setae. Abdomen much compressed, the male without 

 ventral hooks beneath on segment i ; transverse median carinae 

 on segments i , 2 and 3 ; general color black and yellow. 



Erythrodiplax berenice Drury 



Illustrations of Natural History— Exotic Insects, i : pi. XLVin, f. 3 : 1773. 



Nymph. — Head: caudo-lateral angles rounded, the dorsum 

 behind the eyes with six longitudinal setose ridges, betvv^een which 

 are smooth areas ; labium with 9-10 setae on the labial palpi, and 

 12-13 mental setae (PI. vii, Fig. 2), a group of minute setae at 

 base five or six in number. 



