AQUATIC INSECTS IN THE ADIRONDACKS 509 



/ The 10th. abdominal segment with snhcarinate lateral margins ; 



appendages very long ; lateral setae 0-3 Lad on a 



ff The 10th abdominal segment shorter, cyliudric ; appendages shorter ; 

 lateral setae 5-10 

 g Head a little narrowed behind the eyes; front border of the 



median lobe of the labium entire Libellula 



gg Head not narrowed behind the eyes to the hind angles; front 



border of the median labial lobe crenulate Plathemis 



hh BasaFsegment of the hind tarsus half as long as the second segment ; lateral 



appendages of the abdomen at least three fourths as long as the inferiors ; 



lateral setae 10 or more ; superior appendage of the abdomen suddenly 



contracted at its basal third, the dorsal two thirds forming a long slender 



point 



G Movable hook of labium long and slender, setiform ; teeth much broader 



than high; spines of the eighth segment one half longer than the ninth 



segment; superior abdominal appendage shorter than the inferiors 



T r a m e a 



CO Movable hook of the labium short, hardly longer than the teeth ; teeth 



higher than broad; spines of the eighth segment as long as the ninth 



segment; superior appendage equaling the inferiors Pantala 



NANNOTHEMIS 



There is a single species occurring within the state. 

 Nannothemis bella Uhler 



1857 Nannophya bella Uhler, Acad. nat. sci. Phil. Proc. p. 87 



1861 Nannophya bella Hagen, Synopsis Neur. N. Am. p. 186 



1867 Nannoph y a bella Packard, Am. nat. 1:311, pi. 9, fig. 6 



1893 Nannothemis bella Calvert, Am. ent. soc. Trans. 20:260 (description) 



1895 Nan n o them is bella Calvert, N. Y. ent. soc. Jour. 3:48 (listed from 



Westchester co. and New York) 

 1900 Nannothem is bella Williamson, Dragon flies Ind. p. 327 



This is apparently a somewhat rare species, I have not seen it alive. 

 It is known to be distributed from Quebec and Indiana to Florida. 

 Since the foregoing key was prepared its nymph has been discovered by 

 Mr R. Weith near Elkhart Ind. and he has published some notes on the 

 Hfe history of the species and I have described the nymph (Can. ent. 

 1901. 33:252-255). Mr Weith's notes are abstracted below, and my 

 own description and figure are appended. 



This species occurs in very restricted areas (50 yards in length by 

 25 yards in width from margin of the lake) in two places near Elkhart 

 Ind. Unlike most other Odonata, the imagos do not fly higher than a 

 few feet above the ground, preferring to alight on marsh grasses and 

 bask in the sunshine, where numerous small Diptera suitable for food 



