No. 39] ODONATA OF CONNECTICUT: LIBELLULIDAE 261 



tracted behind segment 3 ; male appendages of segment 2 com- 

 posed of a very large genital lobe, and the two arms of the hamule 

 widely separated and pointed. Superior anal appendages brown 

 at tips, small and with a few minute teeth on ventral surface near 

 apex. 



Female. — Differs from the male in having the sides of the 

 thorax yellow, a yellow stripe on anepisternum of mesothorax; 

 abdominal segments 2-4 with transverse yellow stripe, entire dor- 

 sum of 10, and basal spots on 5-7 yellow. The wings are yellow- 

 ish on their proximal half or third. 



Measurements: total length, male 16-21, female 19 mm. ; length 

 of abdomen, male 13, female 11-14 mm.; length of hind wings, 

 male 14-16, female 14-16 mm.; width of hind wings, male 6 mm. 



The black area on the front is variable and is not always quad- 

 rangular. This is our smallest species of Anisoptera. 



Connecticut. — New Haven, 14, 18, 20 July, 1908 (B. H. W.). 

 New England. — June 7- July 29. 



Tribe Sympetrini Tillyard 



The nymphs of this tribe are of moderate size and the labia are 

 of the typical form figured for Sympctrum, PI. vii. Fig. 4. Adults 

 lack the bend in Mo seen in the Libellulini, have entire triangles in 

 the front wings and are never dimorphic in wing coloration ; the 

 wings at base are never greatly widened and never reach 15 mm, 

 in width in our species. 



Key to Genera 

 Nymphs 



1. Abdomen without a lateral spine on abdominal segment 8 



Erythemis, p. 264 

 Abdomen with a lateral spine on abdominal segment 8 2 



2. No dorsal hooks on abdomen 3 



Dorsal hooks present on middle abdominal segments 4 



3. Prominent bunches of setae on dorsum of segments 4 to 9 



Erythrodiplax, p. 262 

 No prominent bunches of setae on dorsum of segments 4 to 9 . . 



Pachydiplax, p. 277 



4. Dorsal abdominal hooks usually as long as the segments bearing 



them ; abdomen with a dorsal spine on segment 3^^ 



Leucorrhinia, p. 278 

 Dorsal abdominal hooks shorter than the segments bearing them ; 

 without a spine on segment 3 5 



5. Lateral spines of the abdomen long and straight ; extending to the 



tips of the inferior appendages or beyond Celithemis, p. 284 



Lateral spines short and incurved Sympetrum, p. 266 



Adults 



I. Cui arising exactly from the caudal angle of the triangle in the 



hind wing ( PI. xiv, Fig. 3) 2 



Cui not arising exactly from the caudal angle of the triangle in 

 the hind wing (PI. xiv, Fig. i) 4 



"* A few species of Leucorrhinia do not have this spine; these do not, however, 

 occur in Connecticut. 



