ERYTHRODIPLAX. 269 
The males do not differ in colour (except with age), or in the form of the appendages or genitalia of the 
second abdominal segment; their wings are not coloured. 
The females seemingly are dimorphic, or dichromatic, differing as follows :— 
a 2 form I (homeochromatic 2). Thorax black with some yellow spots near the coxe, vertex and frons 
metallic-blue, or frons with a small yellow spot in front of each eye, nasus and lips black, nasus and 
labium each side with a yellow spot, abdominal segments 1 and 2 and most of 3 blackish-brown; hind 
wing with ochraceous or smoky-brown at base out to submedian cross-vein and apex of membranule or 
less, front wing with a still smaller, similarly-coloured area at base. 9 form II (heterochromatic @ ). 
Thorax yellow, a mid-dorsal and, on each side, two ante- and five post-humeral black lines or narrow 
stripes ; vertex metallic-blue with a yellow spot at tip, frons metallic-blue with an anterior, transverse, 
medially interrupted, yellow band, most of nasus, labrum and labium (except a narrow median black band 
on the last) yellow, dorsum of abdominal segments 1-3 chiefly yellowish-red ; wings yellowish at base out 
to first antecubital and submedian cross-vein, and a yellowish or yellowish-brown cloud on the anterior 
half between the origin of the subnodal sector and the midway point from nodus to stigma. ¢ 9. Re- 
ticulation dense . . 1. 1. 1. ww ee ee ee we ew ee). «Subspecies berenice type. 
b. 2 form I (homeochromatic 9). Like form aI, but the wings uncoloured. 9 form II (heterochromatic 
9). Like form aI, but the cloud on the middle of the wings is lacking. <¢ 9. Reticulation 
coarse ww we ww ee ee ee ee we we wee ) .) «Subspeciocs neva. 
As necessitated by the definition of a subspecies in the Code quoted above, these two are connected by 
intermediates, listed below. 
[a. berenice type. 
Lnbellula berenice, Drury, Ilustr. Nat. Hist. i. p. 114 and Index, t. 48. fig. 3 (2 form II, in colours) 
(1770)*; Westwood’s edit. i. p. 118, t. 48. fig. 3 (id.) (1837)*; Olivier, Encyc. Méth., 
Insectes, vii. p. 569 (1792)°; Say, Journ. Acad. Nat. Sci. Philad. viii. p. 25 (1839) *; 
Le Conte’s edit. ii. p. 399 (1859) °; Ramb. Névr. p. 88 (1842) °. 
Diplax berenice, Hagen, Syn. Neur. N. Amer. p. 178 (1861)"; Proc. Bost. Soc. Nat. Hist. xv. 
p- 266 (1873)°; Packard, Amer. Nat. i. p. 311, t. 9. figg. 3 (¢), 4 (@ form IT) (1867)? ; 
Guide Stud. Ins. p. 605, figs. 589, 590 (id.) (1869) *°; Uhler, Sci. Res. Chesap. Zool. Lab. 
J. Hopk. Univ. 1878, p. 33”. 
Trithemis berenice, Kirby, Cat. Odon. p. 19 (1890) ”; Ris, Ent. News, xiv. p. 218 (1903) ™*. 
Micrathyria berenice, Karsch, Berl. ent. Zeitschr. xxxiii. p. 871 (1890); Calv. Trans. Amer. Ent. 
Soc. xx. p. 260 (1893); Proc. Calif. Acad. Sci. (2) iv. p. 538 (1895)**; Journ. N. Y. Ent. 
Soc. in. p. 47 (1895) "7; Ent. News, xiv. p. 276 (1903); xv. p. 174 (nymph) (1904); 
Howard, Insect Book, t. 41. figg. 1-3 (¢ 2 2) (1901) *; Brimley & Sherman, Ent. News, 
xiv. p. 101 (1904)”; Butler, Trans. Amer. Ent. Soc. xxx. t. 7. fig. 3 (labium) (1904) ”. 
Erythrodiplax berenice, Calv. Occas. Papers, Bost. Soc. Nat. Hist. vii. 6, p. 86 (1905) ”. 
Libellula histrio, Burm. Handb. Ent. ii. p. 849 (1839) *; Calv. Trans. Amer. Ent. Soc. xxv. p. 63 
(1898) ”°. 
Males and both forms of females are frequent at the same place on the same day. Reticulation as in nos. 1 
and 2 of table on p. 268. 
Had. Unrrep States, Milton in Massachusetts®2? to 171124 Beaufort in North 
Carolina *?. 
A sea-coast species, whose larve live in brackish water!*. The perfect insect is, 
however, occasionally found near Philadelphia , and one individual is recorded 
from Thousand Isles, New York, in the St. Lawrence River. | 
BIOL. CENTR.-AMER., Neuropt., December 1906. In 
