CORDULEGASTER 
The Known Nymphs 
155 
Species Length Lat. spines Lat. Set. | Ment. Set. Described by 
on&8& 9 
diadema 35 none 5 8-9 Ndm. ’04, p. 697 
diastatops 40 stout 5 Cabot ’72, p. 13 
dorsalis 35 none 6-7 8-9 Ndm. ’04, p. 696 
maculatus 41 minute 5 10-11 Ndm. ’01, p. 477 
obliquus 39 stout 6 13 Ndm. 06’, p. 3 
sayi 34 stout 5 i Ndm. ’03, p. 267 
113. Cordulegaster diadema Selys 
Selys ’68, p. 68: Mtk. Cat. p. 76: Kndy. 717, p. 515 (figs.). 
Length 78 mm. Expanse 100 mm. Ariz. 
A fine big species of the southwest, its black body striped on the thorax and 
ringed on the abdomen with yellow. Face pale, with a blackish cross-stripe just 
below the ridge of the frons and a black clypeus and labral border. Occiput 
brown, low, hair-fringed. Pale stripes of the thorax pointed downward and 
strongly divergent. Those of the sides of the thorax broad and regular. Legs 
black. Wings hyaline; costa yellow; stigma brown. Abdomen black, ringed with 
yellow. Segments 3 to 8 each with a single median ring that is angulated at the 
side and bent forward at its lower end; on 9, similar, but broader and nearly 
divided in the middle; on 10, broken into three small spots. Segment 2 mostly 
yellow. Appendages black. 
114. Cordulegaster sayi Selys 
Selys ’54, p. 104: Mtk. Cat. p. 78. 
Length 62 mm. Expanse 78 mm. Me., Va., Wis., Ga. 
A fine eastern species. The face is pale, with clypeus and border of labrum 
brown. The occiput is pale with very narrow black edging next the eyes. The 
black of the thorax is a little more extensive, so that the pale stripes of the front 
are shortened and rounded below; those of the sides are broad, and the black that 
intervenes between these stripes is undivided. Legs black. Wings hyaline with 
yellow costa, and tawny stigma. Abdomen half-ringed above with yellow on 
segments 2 to 9, the rings on 2 to 6 being double, and on 7 to 9 single but broader. 
Segment 10 and appendages black. 
Muttkowski (’08, p. 79) reports that this species is found about Wis- 
consin lakes from June to August. 
115. Cordulegaster erroneus Hagen 
Hag. ’54, p. 688: Mtk. Cat. p. 76: Garm. ’27, p. 121. 
Length 78 mm. Expanse 102 mm. Pa., N. C. to Ky. 
A fine large species with cross-banded abdomen. Face yellowish, except for 
the clypeus and labral border, and the extreme side margins of the frons which 
