AQUATIC INSECTS IN NEW YORK STATE 269 



most of the mentals in a stronger series. Median labial lobe 

 fringed except in the middle, where there is the usual bifid 

 median tooth, each half of which in this species and in d i a s t a - 

 tops is again bifid; but in this species it is about equally 

 bifid, i. e. the two lobes thus formed a.re about equal in size, while 

 in diastatops the lower lobe is much smaller, scarcely ris- 

 ing above the level of the fringe. 



CORDULIINAE 

 SOMATOCHLORA 



Since Bulletin 47 was written, I have obtained nymphs of two 

 additional species of Somatochlora; and, while neither of them is 

 bred, I deem it worth while to describe them now, in order that 

 the new characters they present may allow a better defining of 

 the genus. The characters which I stated with due caution in 

 the table of nymphs {loc. cit. p. 485) now need amplification in 

 but one minor particular: the dorsal hooks, while not cultriform, 

 may be, as in these two species, sharply pointed. 



Somatochlora sp.? no. 2 



Length 24mm, abdomen 15mm, hind femur 8mm, antenna 

 6mm ; width of head 6.2mm, of abdomen 8mm. 



Body stout, moderately depressed, very hairy on the antennae, 

 sides of head and thorax, legs and base of abdomen; head wider 

 than long, eyes small, capping the anterolateral angles; head 

 narrowed behind the eyes to the broadly concave hind margin; 

 legs slender, with faint, subapical rings of brown on the femora; 

 wing cases reaching the base of the sixth abdominal segment; 

 abdomen triquetral, widest on segment 6, slightly narrowed on 

 7, more narrowed on 8, strongly narrowed on 9, in so much that 

 segment 10 is less than half as wide as 9 at base; segment 10 

 very short, annular, included in the dorsally emarginate apex of 

 9; appendages as long as segments 9 and 10 together, the in- 

 feriors slightly longest and the superior a very little longer than 

 the laterals; lateral spines on segments 8 and 9 equal in length 

 to one third or one fourth of the length of their respective seg- 

 ments, those of the ninth hardly longer than those of the eighth 

 segment; dorsal hooks on segments 4-9 similar, but stouter on 

 segments 7-8, and spinulose on their very convex, superior mar- 

 gins on 6-9 (their inferior margin viewed laterally). 



Labium with seven lateral setae and 11-12 mental setae, each 

 side of which the fifth (counting from the side) is longest, and 

 the outermost 7-8 constitute a stronger series. Teeth on the 



