86 DRAGONFLIES OF NORTH AMERICA 
The Known Nymphs 






Relative lengths 
Species Length | Med. | Teeth | Dorsal |__ —_— Lateral Described by 
lobe hooks | g19 |10 app spinest 
adelphus 29 convex | 7-11 8-9 10 | 3] 8 6-9 Hag. ’85, p. 262 
amnicola straight 5 0 6-9 Ndm. & Hart ’01, p. 83f 
confraternus| 28 slightly | 6-9 4-9 6-9 Ndm. '04, p. 291 
convex = 410 
crassus 34 straight | 8-9 8-9 LOR Foro: 6-9 Brtn. '28, p. 32 
14%X10 
dilatatus 42 atraight-| 5-6 8-9 10| 4/6 6-9 Ndm. '03, p. 266 
ish 2X10 
externus 32 slightly | 5-10 8-9 10} 21/9 6-9 Ndm. ’01, p. 451 
convex 2X10 
fraternus 31 convex | 7-11 8-9 10} 3/8 6-9 Ndm. '03, p. 264 
hybridus 28 slightly | 8-9 8-9 10 | 3] 5 6-9 Brtn. ’28, p. 32 
convex 2X10 
scudderi 38 slightly | 3-6 0 10/3)4 6-9 Ndm. ’01, p. 457t¢ 



convex 
concave | 4-5 

31 Cabot. '72, p. 3* 

vastus 

t Lateral spines on segments 6 to 9, on 9 equalling. 
t+ Also in Walk. '28, p. 55 and 87. * Also by Hag. ’85, p. 265. 
This table includes only known nymphs of the larger wide-clubbed 
species (Gomphurus proper). Nymphs of two species of the smaller 
group are known (Needham ’01, pp. 448 and 449): G. abbreviatus 
(length 24 mm.) and G. brevis (length 26 mm.). These two are alike 
in all the characters named in the table, having the median lobe of the 
labium convex, the lateral lobe armed with 8 to 9 teeth, very rudi- 
mentary dorsal hooks on abdominal segments 8 and 9, the relative 
length of segments 8, 9, 10, and appendages as 9:10:4:8, and lateral 
spines on segments 6 to 9. Those of 9 being as long as the tenth seg- 
ment. The real difference between these two species is found in the 
length of the foremost lateral spines, those of the 6th segment in 
G. abbreviatus being less than half, and in G. brevis more than half the 
length of the spines of the 7th segment. In form of the flat blunt- 
tipped body these nymphs resemble those of Gomphurus proper. 
KEY TO THE SPECIES 
G. consanguis (p. 94) omitted: see key on p. 82 
Adults 
1 Short, stocky species (ex. 50-60 mm.) with little widening of the 
club (segments 7 to 9) of the abdomen.................... 2. 
Larger forms (ex. 60-95 mm.) with a great widening of the club 
Gf the abdomieny, oot. oo. sig: aa bg en ole ee eee 6. 
2 Face yellow including the labrum............ abbreviatus, p. 89 
Face.cross:striped with black «.. «5.5 .\.c:icieeeseneee te te ees 3. 
