488 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.52. 



of uncatus} Teeth along distal edge of mentum and on internal 

 edge of the lateral lobe similar to those figured by Walker for ungui- 

 culafus.^ Antenna seven jointed. 



Wings short, reaching beyond middle of third segment. Lateral 

 spines on segments 5-9. Hind femur reaching to beyond apex of 

 third segment; 8-11 spicules on lateral carina of segment 9. Ovi- 

 positor reaching just beyond apex of segment 10 and styH of valves 

 slightly beyond ovipositor. Ventral edge of valves with a row of 

 five or six minute spinules, no hairs. Gills sickle-shaped, the median 

 curved down and the two laterals curved up, each broadest at the 

 proximal third, tapering thence to the obtusely pointed apex. Edges 

 of gills with conspicuous spinules (none on uncatus). Each gill with 

 three spots on its dorsal edge and tln-cc on its ventral edge. Apices 

 of femora with a dusky ring, otherwise no color pattern. Length 

 without caudal gills, 21-23 mm.; giUs, 12 mm.; hind femur, 5.5 mm. 



The nymph of stultus, if that is what these specimens are, is close 

 to that of disjundus. Since writing the preceding description I 

 reared a disjundus nymph from these same Mud Lakes. This reared 

 nymph agrees in detail in size, numbers of spines, etc., with Walker's 

 description of disjundus nymph. On comparing it with the stultus 

 exuviae I find these larger, the caudal gills hardly as acuminate, the 

 spicules on the lateralkeel of segment 9, 12-13 in number. I should 

 have supposed that the stultus nymph would be closer to uncatus. 



3. A NEW GENUS BASED ON AGRION EXCLAMATIONIS. 



ZONIAGRION, new genus. 



Arculus placed at or near the second antenodal; Mj arising basad 

 of the sixth postnodal in the front wing and basad of the fifth post- 

 nodal in the hind wing; anal bridge separating from the hind margin 

 of the wing as far before the anal crossing as the latter is long; 

 three post-quadrangular cells; antenodal costal spaces with the 

 second space shghtly more than half the length of the first and 

 shghtly less than half the length of the third; quadrilateral of fore 

 wing with basal side contained in the distal side 2-2.75 times and in 

 the posterior side 3.5 times; anterior side varying greatly, from 1-2 

 times length of basal side. Stigmas alike in front and hind wings; 

 costal andposterior margins equal; either shghtly longer than the 

 proximal or distal margins, which are equal. 



Female with a large apical spine on the ventral side of segment 8. 

 Male with segment 10 terminating dorsally in a fork which is shghtly 

 higher than the anterior end of the dorsum. Shaft of penis with 

 spines, the tip spatulate; distinguished from that of 110 other agri- 

 onine genera examined, including all the North American genera, by a 



1 See Can. Ent., vol. 46, p. 199, pi. 14, fig. 9, uncatus, mental lobe. 



2 Idem, p. 349, pi. 23, fig. 1, unguiculatus, mental teeth. 



