2l6 CONNECTICUT GEOL. AND NAT. HIST. SURVEY [Bull. 



necticut when found may be regarded as largely accidental. They 

 are said to be crepuscular or twilight fliers and this apparently 

 holds true for the few that have been collected in this State. 

 According to Walker (1925) there are two types of oviposition, 

 depending on the type of ovipositor. The eggs are laid while the 

 insect is on the wing, however, varying only in the locality in 

 which the eggs are deposited. Such species as forcipata, albicincta 

 and cingulata are said to oviposit in water or wet moss, the act 

 being accomplished by striking the abdomen while in flight. The 

 species linearis and williamsoni lay their eggs in wet sand, by a 

 similar procedure. 



For literature dealing with this genus see — 

 Kennedy, C. H. Canadian Entomologist, 49: 229-236: 1917, pi. xiii. 

 Walker, E. M. Canadian Entomologist, 50: 365-375: 1918, pi. x. 



University of Toronto Studies Biological series No. 26: 1925; 202 pp., 



34 pis. The best and most complete work on this genus in America. 

 Williamson, E. B. Entomological News, 20: 77-79: 1909. 



In drawing up keys and descriptions of this genus free use has 

 been made of the work of Walker, 1925. The description of 

 nearly all nymphs have been taken direct from that monumental 

 work, though it has been impossible to make use of all the descrip- 

 tive matter presented therein. The genus Somatochlora is divided 

 by Walker into six groups which should be mentioned here, 

 together with the Connecticut species belonging to the different 

 divisions. They are (i) the metallica group containing minor, 

 elongata, williamsoni, and walshii; (2) the linearis group con- 

 taining linearis; (3) the tenebrosa group with tenehrosa; (4) the 

 filosa group with filosa and provocans; (5) the arctica group, 

 containing franklini, kennedyi and forcipata, and (6) the alpestris 

 group containing albicincta and cingulata. 



Key to Species^ 

 Nymphs 



1. Dorsal hooks present 2 



Dorsal hooks absent ^ 



2. Dorsal hooks falciform, acute, the last one projecting beyond the 



middle of segment 10 .•••;•• 3 



Dorsal hooks low knobs, not falciform, the last one not projectmg 

 to middle of segment lO wiUiamsom 



3. Median appendage of male fiat above, the ante-apical tubercle (apex 



of developing inferior appendages of adult) not at all elevated 4 

 Median appendage of male longitudinally concave, the ante-apical 

 tubercle slightly elevated tenebrosa 



4. Lateral spines at least half as broad as long; lateral appendages 



shorter than segments 9 and 10 together ; median appendage not _ 



acuminate lineans 



Lateral spines less than half as broad as long; lateral appendages 

 as long as segments 9 and 10 together ; median appendage acumi- 

 nate with a very slender tip 5 



M Adapted from Walker, 1925. Species in parenthesis are not described in this paper. 



