AQUATIC INSECTS IN THE ADIRONDACKS 481 



Imagos 



a Dorsal surface of tlie bead with the oceipat larger than the vertex; sub- 

 triangle of the fore wings usually divided by a cross vein ; four to six cross 



veins in the space above the bridge {see fig. 9) Didymops 



aa Dorsal surface of the head with the occiput much smaller than the vertex ; 

 subtriaugle of the fore wings generally open; two or three cross veins in 

 the space above the bridge ., Macromia 



JVymJ>/is 



a Head hardly as wide across the eyes as across the bulging hind angles ; 

 lateral spines not incurved, those of the ninth abdominal segment hardly 

 surpassed by the tips of the appendages ; dorsum of the 10th abdominal seg- 

 ment with no trace of a dorsal hook Didymops 



aa'Head widest across the eyes ; spines of the ninth abdominal segment shorter, 

 not nearly reaching the level of the apices of the appendages; dorsum of 

 the 10th segment with a very rudimentary dorsal hook Macromi a 



DIDYMOPS 



There is a single species. 



Didymops transversa Say 



1839 Libellula transversa Say, Acad. nat. sci. Phil. Jour. 8:19 

 1861 Didymops transversa Hagen, Synopsis Neur. N. Am. p. 135 

 1875 Macromia transversa Hagen, Bost. soc. nat. hist. Proc. 18 : 57 



(full bibliography, and distribution) 

 1890 Macromia transversa Cabot, Immature state Odon. pt 3, p. 14-16, 

 pi. 1, fig. 3 (full bibliography, description of nymph and distribution) 

 1893 Didymops transversa Calvert, Am. ent. soc. Trans. 20:250 (de- 

 scription) 



1899 Didymops transversa Kellicott, Odon. Ohio, p. 88 (description) 



1900 Didymops transversa Williamson, Dragon flies Ind. p. 307 (de- 



scription) 



This is a common species in woodland streams and ponds, in water 

 of a little depth, in shaded pools, etc., where there is little vegetation. 

 It was not very common at Saranac Inn, but nymphs were taken in the 

 borders of Little Clear pond and creek, and exuviae were found along the 

 eastern shore of Lake Clear, hung up in the bushes, or attached to large 

 rocks several yards from the water's edge. Imagos were observed only 

 about the borders of the larger bodies of water. They could always be 

 seen darting in and out of the edges of the woods on the fragrant shores 

 of Little Green pond. 



Nymph. (PI. i8, fig. 8) Measures in total length, ^27 mm, ? 29 

 mm; abdomen 19mm: hind femur 11 mm; width of head 7 mm, of 

 abdomen 13 mm. Body flat, thin edged, with legs wide apart at bases 

 and sprawhng. Color yellowish below, mottled brownish above, the 



