CORDULEGASTER. 173. 
The other eight species are North American; some of them have been reported from 
Nova Scotia and Alaska, while one of the forms mentioned below reaches 10° North, or 
considerably farther southward than the genus has yet been found in the Old World. 
No structural differences appear to exist between the two “species” of the present 
fauna, and some of the colour-differences, based on fewer specimens than those now at 
hand, prove to be variable. They agree in having the anterior surface of the frons 
dark-coloured, the abdomen with transverse, submedian, yellow rings on segments 2-9, 
the eyes in contact dorsally (although for hardly more than a point), and the superior 
appendages of the males bidentate inferiorly. Their most constant differences are :— 
Frons with a superior, transverse, oval, yellow spot; transverse, submedian, yellow 
rings on 2-9 wider (on 3-7 at least 1 mm. wide), not interrupted on the mid- 
dorsal line of 2-5 (and sometimes other segments): abdomen, ¢ 57-63, 
? 60-64; hind wing, g 48-48, 9 50-53mm. ...... =.=. +... J. diadema. 
Frons with no yellow spot ; transverse, submedian, yellow rings on 2-9 narrower (on 
6 and 7 a mere line, a little wider on 3-5), interrupted on the mid-dorsal line of 
3-7 (and sometimes other segments): abdomen, ¢ 54-66, 9 58-67; hind 
6 
wing, ¢ 45-52, 2? 50-56mm. . .... . ee ee ee ee ee Qe godmani. 
1. Cordulegaster diadema. 
Cordulegaster diadema, Selys, Compte Rend. Soc. Ent. Belg. xi. p. Ixviii (1868)"; Bull. Acad. 
Belg. (2) xxviii. p. 203 [40] (1869)?; Currie, Proc. Ent. Soc. Wash. v. p. 303 (1903) *; 
Needham, Proc. U.S. Nat. Mus. xxvii. p. 697 (1904)* (supposed nymph). 
All of the present material have a brown median line on the labrum from the base halfway toward the free 
margin. Only one individual (from Cuernavaca) lacks a representative of the ‘“raie interméddiaire jaune 
aux cotés du thorax”; all others have a superior yellow spot, although often quite small, to mark its 
position. The transverse, submedian, yellow, abdominal rings may be interrupted on the mid-dorsal line 
on one or more of segments 6-9. The Ventanas male has the occiput black, fringed with white hairs, 
the labrum with a black border on all sides; a somewhat similar labral colour-variation has been found 
in the European annulatus (Selys, Monogr. Gomph. p. 336). 
Hab. Unirep States, Bright Angel, Arizona *.—Muxico (U. S. N. M.: 1 3), Ven- 
tanas (Forrer: 1 3), Santa Fé, in the Distrito Federal [4 ¢,1 9], Cuernavaca! 
[5 ¢,1 2 | (Barrett, coll. P. P. C.; coll. McLachlan: 1 3), Orizaba?! 2. 
Taken in July at Bright Angel?, in October and November at Santa Fé and 
Cuernavaca. 
2, Cordulegaster godmani. 
Cordulegaster godmani, Mclachlan, Ent. Monthly Mag. xv. p. 85 (1878)'; Selys, Bull. Acad. 
Belg. (2) xlvi. p. 687 [95] (1878) *. 
Occiput yellow in the pair from Omilteme, black in the Purnla male, which is also peculiar in having the 
labrum reddish-brown throughout, the apex of the inferiur appendage narrower (about one-half as wide 
as at base, while the other males have the tip about two-thirds as wide as base), the pterostigma longer 
(4°5 mm. on front wings, as against 3-5-4 mm. in other individuals), and the maximum dimensions 
as given above. The “ partie centrale plus claire”? of the upper surface of the frons is not evident even 
on the types. The pair from Omilteme alone have no vestiges of the ‘bande intermédiaire” on the 
