274 DRAGONFLIES OF NORTH AMERICA 
2 Lateral spines present on abdominal segments 2-, or 3-9. Gills 
not sharply ‘pointed YP 2 2e7 sien ae eee) Se vigilax. 
Lateral spines present on abdominal segments 4-, or 5-9...... 3. 
3 Lateral spines present on segments 4-9. Mentum from five and 
one-half to five and three-fourth millemeters long. Mental 
setae 7 or 8. Hind femora 6 mm. long, outer wing pad 6.5 mm. 
WOT re ssh etatatels Stats lahat ta eite ceva ak en Cn a eurinus 
Lateral spines on segments 5-9. Mental setae usually 5-6, often 
7. Hind femora less than 6 mm. long, outer wing pads 5.5 mm. 
longer lessee OCA eee ae: cae nae een 4. 
4 Mentum of labium more than 4.2 mm. long, reaching generally to 
the apex of the hind coxa or beyond. Ovipositor extending 
beyond: hind margin of ‘segment“TO?O" rn. eee 5. 
Mentum of labium 3.7—4.2 mm. long, rarely reaching beyond the 
middle of the hind coxa. Ovipositor just reaching the hind 
WIAFRINGOE AO. cies cds 8 on Se 2 he ae banal ola ee 6, 
5 Mentum of labium 4.3-5.1 mm. long, reaching the apex of the 
hind coxa or slightly beyond. Ovipositor 3-3.5 mm. long, ex- 
tending just beyond the basal joint of the gills........ uncatus. 
Mentum of labium 4.75—5.5 mm. long, reaching beyond the apex 
of the hind coxa often to the apex of the trochanters. Ovipositor 
2 mm. long, and extending very little beyond the hind margin 
OPO POE OER, PIMA T EE A OE are eee disjunctus. 
©. « Mental setae Normally 5. si00.6.060.2.4:.). See rectangularis. 
Mental setae Normally 6-7.............06..000.00485 forcipatus. 
Nymphs* 
Lat. 
Species Lengtht | spinest |Lat. Set.§|Ment. Set.§ Described by 
congener 20+9 5-9 4-5 7 Walk. ’14, p. 191 
disjunctus 19+9 5-9 3 5-6 Walk. ’14, p. 196 
eurinus 25+11 4-9 3 7-8 Walk. ’14, p. 192 
forcipatus 17+9 5-9 3 6-7 Walk. ’14, p. 196 
rectangularis 20+9 5-9 3 5 Ndm. ’03, p. 231 
stultus 22+12 5-9 3 a Kndy. 717, p. 487 
uncatus 23+9 5-9 3 5-6 Walk. 714, p. 195 
unguiculatus 234+8 5-9 3 of Ndm. ’03, p. 233 
Vigilax 22+10 | 2 or 3-9 3 5 Walk. 14, p. 198 
* forficula: 18+9 5-9 3 5 Calv. ’28, p. 8. 
{ Length of body + gills.. 
t Of abdomen on segments. 
§ Of labium. 
