112 DRAGONFLIES OF NORTH AMERICA 
for a low rudiment on the ninth abdominal segment. Sometimes there 
is a median ridge before it but there is no median groove or impressed 
line. Segment 10 is long and cylindric and the long vertically flattened 
spines of 9 are closely applied to its sides. There are lateral spines on 7, 
or 8 to 9, only. 
The following table sets forth the more salient characters of the 
nymphs of the species hitherto described. 
The Known Nymphs 

Dorsal | Felative lengths Watered 
Name Length | Teeth | hooks || _ spines* Described by 
8 | 10 | 10} app 
furcifer 33 6-7 0 8|10|6)] 4 8-9=1/5 | Walk. ’04, p. 358 
of 10 
pallidus 38 8 9 Sa eLON EG! |e 7-9=10 | Hag. ’85, p. 266 
submedianus 38 6-7 9 “| 10) 5 4 7-9 =10 Ndm. & Hart ’01, p. 79 
villosipes 35 6 0 ff |) 1) | Gy\ e! 8&-9=1/5 | Ndm. ’01, p. 460 
* And length of 9 in terms of length of 10. 
KEY TO THE SPECIES 
Adults 
t, Oceiput bordered ‘with black. .... . .techkt-emeber villosipes, p. 
Occiput:not: bordered withoblack.«! 5 i2058..2 Sae an eee 
2, Abdominal appendages black, . 1 <.\-icui eet eee eae 
Abdominal appendages not. black 7 tynce a. eran eee 
3 Superior appendages of male forked and with a long external tooth 
BalhS ss. 5< OES al etic wa ice euee nak Shae eg Deuce eae eer an One cornutus, p. 
Superior appendages of male merely angulate externally..... 
ae Le COORG Seay hy 7 ee DR UR SN Se 2 eS whedoni, p. 
A.) Seripe-o) COMMMCEE as Se cas Ate heen es ak lentulus, p. 
Stripe:S.obaoletecor wanting: /fu! six ¢!orn id) bane 
5 “Stripes 2 and S*conjomed ‘above’. 022.007 7. one furcifer, p. 
Stripes 2 and 3'not conjoimed above: °° .0 7°.) oo se eenas 
6 Femora and tibiae uniformly pale.............. pallidus, p. 
Femors and tibiae partly, black: | 6. 27.4. 4. oe 
¢, -Stnipes:2 and: 3-subequaly tics este ae. Fee subapicalis, p. 
Stripes 2 and 3 reduced toaline.......... submedianus, p. 
115 
stone 
