434 



NEW YORK STATE MUSEUM 



Family aeschnidae 

 This family contains four subfamilies that are so different in character 

 and habits they may be best discussed separately. The following keys 

 will serve for their separation. 



KEY TO SUBFAMILIES 



Imagos 

 a Stigma braced at its inner end against an inclined cross vein in the space 

 below it (see fig. 9) 

 h Cnbital vein in the fore wing extending directly to the hind angle of the tri- 

 angle, not appearing forked ; subtriangle consisting of one cell, or 

 indistinctly developed 



c Eyes widely separated on the top of the bead Gompbinae 



CG Eyes approximated on the top of the bead Aescbninae p. 462 



b1) Cubital vein in the fore wing apparently forked at the base of the second 



cubito-anal cross vein; subtriangle of three cells. Petalurinae p. 472 



aa Stigma without a brace vein Cordulegasterinae p. 473 



Nymphs 

 a Labium flat (or with the edges of the lateral lobes slightly upturned in 

 Tachopteryx), and without raptorial setae 

 6 Labium with its median lobe entire ; antennae four jointed, the fourth joint 

 rudimentary; fore tarsi two jointed : burrowing nymphs. Gompbinae 



hi Labium with a short median cleft (fig. 8B) ; antennae seven jointed, 

 setaceous; tarsi three jointed ; climbing nymphs, with eyes at sides of head 



Aeschnin ae 



hhh Labium with a shallow median cleft (fig. 15); antennae seven jointed, 



short ; squatting nymphs, with face vertical, and eyes on anterolateral 



angles; depressed, hairy ; tarsi three jointed Petalurinae 



aa Labium spoon sbaped, with raptorial setae, differs from libellulid nymphs 

 in having the prominent median lobe of the labium cleft into two vari- 

 ously formed teeth at apex (fig. 16) Cordulegasterinae 



Subfamily qoimfhinae: 



Mostly large species, with clear wings, bodies striped with black and 

 green or yellow, of strong but not well sustained flight, inhabiting mostly 



§&^7\ - 



J m 



Fig. 10 Diagram iUustrating the parts of the bead and thorax chiefly used in the tables (Lan 

 thus albistylus Selys.). ^head seen from front; eeye; /frons; ij postclypeus ; ganteclly 

 peus; rlabrum: s edge of labium ; * side of mandible ; otgena: u vertex, bearing the three ocelli 

 and the antennae ; o occiput. B Thorax from the side ; m prothorax ; n abdomen ; a and 6 consoli- 

 dated meso- and metathorax ; b collar; c carina; d crest; x,y,z&vst (humeral;, second and third 

 latural sutures and stripes ; 2 and 3, bases of middle and hind legs respectively 



