No. 39] ODONATA OF CONNECTICUT: CORDULEGASTERIDAE II9 



The nymphs of this genus are almost without exception found 

 in small streams, the adults usually near the habitat of the nymph. 

 The reared nymphs of maciilatus, the only species which we have 

 been successful in bringing through, were both found in small, 

 rapidly flowing streams in shady locations. The adults are com- 

 paratively slow on the wing and more easily captured than the 

 various Aeshnas or Libellulas. In captivity the nymphs will 

 burrow into sand, leaving only the tip of the abdomen and the 

 head protruding, and are very quick at capturing a struggling 

 insect if brought within range of the labium. 



For literature dealing witli adults of the genus, see Needham, J. G., New 

 York State Museum Bulletin 47: 474-478: 1901. 



Key to Species 



Adults " 



Males and Females 



1. Abdomen with a mid-dorsal line of yellow spots, those on seg- 



ments 3-8 arrow-shaped obliquus 



Abdomen without a mid-dorsal line of yellow spots ; either with 

 a double row of yellow spots or with transverse yellow bands . . 2 



2. Abdomen with transverse yellow bands, at or about the middle of 



terga 3-8 3 



Abdomen without transverse yellow bands, but with yellow spots 

 on either side of the meson 4 



3. Face yellow ; eyes not contiiguous [sayil 



Face blackish ; eyes contiguous at a single point on the meson erroneus 



4. Terga 2, 3 and 4 each with 4 small, somewhat circular yellow 



spots ; eyes cxjntiguous on the meson maculatus 



Terga 2, 3 and 4 each with 4 small elongate yellow spots, the spots 

 on each side of the meson in line, and contiguous on the different 

 segments ; eyes well separated at the meson diastatops 



Cordulegaster diastatops Selys 



Bulletin de I'Academie royale . . . de Belgique (2), 21: loi : 1854. 



Adult, male. — Color brown, marked with yellow. 



Head : labium brown ; labrum, postclypeus, front and vertex, 

 except the brown caudal margin, yellow ; anteclypeus, preocular 

 stripe and frontal vesicle, dark brown or black ; rear of head light 

 brown and yellow, dorsal margin behind the compound eyes shiny 

 black ; eyes separated by about .5 mm. on the dorso-meson. 



Thorax : prothorax light brown, the caudal margin darker, 

 meso- and metathorax brown with 3 yellow stripes, the dorsal 

 stripe cuneiform, i mm. wide, the upper end rounded, lower end 

 tapering; first lateral or mesepimeral pale stripe 1.5 mm. wide by 

 5-6 long, metepimeral about the same dimensions, the sides nearly 

 parallel and the ends rounded ; legs dark brown or black, the 

 trochanters with an irregular glabrous area beneath, femora with 



Only the nymph of maculattts has been reared; key adapted from Needham. 



