No. 39] ODONATA OF CONNECTICUT: LIBELLULIDAE 



265 



also with spines arranged in an irregular row ; distal margin of 

 mentuni spinose; antennae with third, fifth, and sixth segments 

 longest and subequal ; others shorter ; the caudal margin of the 

 eyes viewed from above are about the middle of the lateral margins 

 of the head; dorsal surface of the head behind the eyes with 6 

 longitudinal setigerous stripes in older nymphs. 



Thorax : pronotum sloping cephalad sharply from the spiracles 

 and with a setose elevation on meson just behind the middle; 

 lateral margins of pronotum also setose ; femora with a few 

 scattered heavy setae on dorsal surfaces and at apices, the tibiae 



Fig. 66 

 enlarged. 



Labium of the nymph of Erythemis simplicicolUs, greatly 



also with heavy setae; tarsi with claws about as long as the first 

 segment ; wing-cases in older specimens reaching to the middle of 

 the seventh abdominal segment (in alcoholics, to segment 9) ; 

 venter of thorax with a conspicuous setose ridge on mesosternum 

 just behind the first coxae. 



Abdomen : ovate ; the lateral keels without spines or with rudi- 

 mentary ones, more frequently without; terminal appendages 

 broad at base, the superior and ventral nearly equal in length, 

 laterals one-half as long as the superior in full-grown, less than 

 one-third as long in younger nymphs. 



Measurements: total length, 15-16 mm.; length of abdomen, 

 8 mm. ; length metathoracic wing-cases, 5-6 mm. ; length hind 

 femora, 4.5-5 mm. ; length median lobe, 4 mm. ; width, 1.5-4 mm. 



