ANAX. L75 
the hind wings extending along the anal margin for a distance 
equal to or greater than the distance along which it extends on 
the postcosta (except in 4. castor) . . . . . . . . .).)~6-ASSHNA. 
EE. Eyes in contact for a distance greater than the antero-posterior 
dimension of frons and vertex combined; membranule of the 
hind wings not extending along the anal margin, or, if so, for a 
distance less than its postcostal extent. Males with no (or but 
rudimentary) dorsal teeth or carinze on abdominal segment 10; 
females with long inferior spines on this segment . . . . . GYNACANTHA. 
CC. Subnodal sector not forked or branched. Two rows of cells between 
principal and nodal sectors beginning proximal to the level of the 
pterostigma ; three rows of cells between nodal and subnodal sectors 
at the level of the pterostigma ; no basal subcostal cross-veins ; proximal 
side of triangle of the hind wings more than half as long as the distal 
(posterior) side; no ventral tubercle on the first abdominal segment. 
Males with the anal triangle 8-celled . . . . . . . . «~~ OPLONESCHNA. 
BB. Supplementary sector next below the subnodal sector (which is forked) 
subparallel to the posterior branch thereof and separated therefrom by 
two rows of cells; two or three rows of cells between the short sector 
and the supplementary sector next below, at the level of the nodus; 
anal loop on the hind wings elongated at right angles to the long axis of 
the wing 2. 6 we we ee ek ee ee ee CE resco. 
As in the other generic synopses in this work, I have sought to characterize each 
genus as absolutely as the material at hand and the literature will permit and not 
merely with reference to the fauna in question. ‘This is highly desirable in order to 
enable the reader to detect the occurrence of other genera in Mexico and Central 
America than those here named. The discovery of additional genera and species is 
highly probable, owing to the great powers of flight possessed by members of this 
subfamily. 
It should be added that in the above synopsis I have not made as much use of 
characters drawn from the anal loop as has been done by Messrs. Needham and Hart 
in a recent paper *, because, from an examination of the material before me, I do not 
believe that the loop has as much constancy of shape as they ascribe to it. 
ANAX. 
Anazx, Leach, Edinb. Encye. ix. p. 137 (1815)"; Amer. edit. (Phila,) viii. pt. 2, p. 726 (1816) ?; 
Brauer, Reise d. Novara, Neur. pp. 60-63 (1866)*; Kirby, Cat. Odon. p. 83 (1890)*; Karsch, 
Ent. Nachr. xvii. p. 287 (1891) ’. 
* “The Dragon-flies (Odonata) of Illinois.—Part I. Petaluride, schnide, and Gomphide,” Bull. Ill. St. 
Lab. Nat. Hist. vi. 1, pp. 30, 31 (1901). 
