274 



PSYCHE. 



[August 1895. 



NEW NORTH AMERICAN ODONATA. — II. 



BY ALBERT V. MOUSE, WELLESLEV, MASS. 



Nehalennia gracilis sp. nov. 



Very sitnilar to N. irate but even slenderer 

 and differing in structure and markings. 

 Post-ocular spots present in the shape of a 

 continuation of the occipital line hall-waj to 

 eacli eye. $ : segments 9 and 10 all blue ; 

 8 blue e.\cept a very narrow transverse basal 

 band. Superior appendages one-third (when 

 well extruded) as long as the side of 10, in 

 side view about two-thirds as broad as long, 

 directed backward, upper margin conve.\, 

 lower margin slightly concave, apex rounded ; 

 in dorsal view about twice as broad as long, 

 the inner margins nearly contiguous, the dis- 

 tal margin parallel with the excised margin 

 of to but a little concave, the lateral and 

 inner margins equal, slightly convex, directed 

 caudad, the outer apical angle well rounded, 

 the inner less so. Inferior appendages very 

 short, the upper outer angle produced caudad 

 into a stout apical tooth which projects 

 nearly as far as the superior appendages ; in 

 dorsal view these teeth are seen at the sides 

 of the latter, directed outward and back- 

 ward, their inner margins concave, outer 

 margins convex. ? : similar to ireiic but 

 the hind margin of the prothorax is excavate 

 medially making it bilobed (instead of tri- 

 lobed as in that species) ; the markings differ 

 in that a large triangular apical spot on 9 

 and all of 10 are blue. In three examples 

 the spot on 9 is produced to base and the 

 dorsum of 8 also is nearly or entirely blue 

 medially, widest behind. 



Abd. : (J, 20-22 ; ?, 20-22. Hind wing: 



<?. i3-'4 5; ?• ■4-i.v 



2 pairs, 13 J", II 5, June 24, Slierborn, 

 Mass.j 6 (J , 2 9 > June ig; i ?, June 27; 

 I J.July 19, Wellesley, Mass. 



Taken near stagnant pools in peat-bogs in 

 company with ireue, with which species it 

 has hitlierto been confused, as shown by the 

 series in the Hagen collection. 



Enallagma laterale sp. nov. 



Post-ocular spots of moderate size. jNIid- 

 dorsal thoracic and humeral dark stripes of 

 medium width. Abdomen blue with the dor- 

 sum black as follows : apical half of 2, fourth 

 of 3, third of 4, half of 5, three-fourths of 6. 

 all of 7 except an interrupted basr.l ring, a 

 stripe each side on S, and all of 10. Dor- 

 sum of 10 emarginate. Superior appendages 

 short, one-fourth to one-third as long as side 

 of 10, in side view nearly as broad as long, 

 directed caudad or slightly deflexed, sides 

 parallel, apex blunt, emarginate ; in dorsal 

 view as broad as long, widened apically, 

 emarginate at end, apex of both limbs show- 

 ing equally, smoothly rounded, the upper 

 presenting a little tooth on inner margin. 

 Seen from the left dorso-lateral aspect the 

 right (and vice versa) appendage is seen to 

 be deeply rounded-emarginate, or slightly 

 bifurcate, the lower limb usually slightly 

 larger and longer. Inferior appendages 

 nearly twice as long as the superior, stout at 

 base but much narrowed dorsally, directed 

 backward and a little upward, sides straight, 

 tapering smoothly to the slightly upturned 

 and incurved tip. 



Abd. : J, 20.5-22. Hind wing: $ , 15-16. 



14 J, May 25 ; 9 cT.JuneS, Wellesley, Mass. 



Enallagma pictum sp. nov. 



Allied to sigiiutuin. Coloration black and 

 yellow. Post-ocular spots reduced to a con- 

 tinuation of the occipital line. A pair of 

 very small pale spots between the anterior 

 ocellus and the posterior two. Dorsum of 

 thorax chiefly black, humeral pale stripes 

 narrow, $, or very narrow, J. $ : abdo- 

 men black as follows : dorsum of i-io, on 2 

 in form of an orbicular apical spot narrowly 

 connected to base, on 3 terminating in a 

 sharp point basally. i with wide apical, and 

 4-7 with narrow'interrupted basal ring, yel- 



