HESPERAGRION. 103 
HESPERAGRION, gen. nov. 
The characteristics of this genus are indicated in the preceding key. Its type 
species, Agrion heterodoxum, Selys, was referred by that author to Amphiagrion, Selys, 
whose type is A. saucium, Burm. In addition to the differences between the imagines 
of Hesperagrion and Amphiagrion given in the key, the nymphs also differ. Prof. 
Needham, who has examined them, writes me of that of A. heterodoxum :—* Surely its 
nymph has nothing to do with Amphiagrion, nor with Pyrrhosoma either... . it seems 
to me, from the study of the nymphs alone, to be as near Jschnura as any of our 
genera.... I think [it] will have to go in a new genus.” (Letter of January 7th, 
1902.) 
1. Hesperagrion heterodoxum. (Tab. V. figg. 11,12; Tab. VI. figg. 1-6.) 
Agrion heterodoxum, Selys, Compt. Rend. Soe. Belg. xi. p. Ixix (1868) *. 
Amphiagrion heterodoxum, Selys, Bull. Acad. Belg. (2) xli. p. 288 (1876) *. 
Agrion heterodoxum, var. flavescens, Selys, loc. cit. p. xx (1868) *. 
Amphiagrion flavescens, Selys, loc. cit. p. 289 (1876) *. 
The following colour variations, most of which have not been noted in the published descriptions, exist :— 
3. (a) Black on the vertex confined to a few lines in the grooves; region of the postocular spots and the 
occiput bright red, which is confluent with the yellowish coloration of the rear of the head. Thorax 
pale brown, with an indistinct darker mid-dorsal stripe. Abdominal segments 1-3, 8-10, and base 
of 4 bright red, unspotted; most of 4-6 dark metallic green, their sides and a narrow basal ring on 
5 and 6 yellow. Evidently teneral.—Cuernavaca, Durango. 
(b) Like the above, except that the vertex is black, the bright red postocular spots are bounded posteriorly by 
black or dark brown, the mid-dorsal thoracic stripe is black, there is a black humeral line, and the thorax 
generally has acquired a pale blue or green tint. Undoubtedly older individuals than (a), but without 
pruinosity.— Arizona, Cuernavaca. 
(c) Vertex black; large bright red postocular spots bounded posteriorly by black. Thorax light blue, black 
mid-dorsal and humeral stripes, the latter narrower, leaving between them a blue antehumeral stripe 
nearly half as wide as the black mid-dorsal, but somewhat narrowed at mid-length. Dorsum of 
segments 1-6 black, a basal ring and the sides pale blue or green; 8-10 bright red, with some obscure 
lateral marks. Not pruinose.—Arizona, Cuernavaca. 
(d) Like ¢, except that each blue antehumeral stripe is broken into two cuneiform spots representing the upper 
and lower ends of the stripe, due to the fusion of the black mid-dorsal and humeral stripes at mid-height. 
Not pruinose.—Arizona, Durango, San Luis. 
(¢) Pruinose; dorsal surfaces of head, thorax, and abdomen dark and obscure ; minute red traces of the post- 
ocular spots distinct in some specimens, entirely absent in others; thorax apparently formerly coloured 
as inc; a faint reddish tinge sometimes observable near the apex of the abdomen. Type of Selys’s 
A, heterodoxum.—Cuernavaca. 
The colour of the seventh abdominal segment appears to vary independently of the colours of the rest of the 
body, since individuals of any one of the variants a—-e may have 7 almost entirely black, or blue with the 
apical fourth black, or from the apical black a black stripe of varying width may extend towards the base. 
Q. (f) Body generally brownish-yellow, becoming more obscure on segments 5-7, many of the inter- 
segmental abdominal articulations darker. More or less teneral in appearance. Type of A. flavescens, 
Selys.—Arizona, Cuernavaca. 
(g) Pale green, some dark lines in the grooves on vertex, the large pale postocular spots bounded posteriorly 
by dark brown or black; a black mid-dorsal thoracic stripe and a humeral line, leaving between them a 
pale green antehumeral stripe half as wide as the black mid-dorsal ; dorsum of 1-2, 8-10 black, 3-6 with 
a black hastate dorsal spot extending from apex almost to base.—Cuernavaca. 
