LEUCORRHINIA 241 
of a pattern of blackish stripes on the paler sides when recently 
emerged. The abdomen is pale at base where striped with black, be- 
coming wholly black at the end. There is little enlargement of the basal 
segment. The anal loop is short and broad, the heel being developed 
about as long as the toe. 
The nymphs are smooth bodied, greenish in color and clamber in 
beds of submerged vegetation. There are dorsal hooks on segments 2 
to 6 or 8, and lateral spines on 8 and 9, the latter never very long. 
The lateral setae are 10 or more, and the mental setae are still more 
numerous. 
The Known Nymphs 
Species L. cee d. h. of 7* d. h. of &* Lat. sp. of 8** | Lat. sp. of 9** Described by 
ooks 
frigida 2-8 =7 =8 =1/2 of 8 = Walk, ’13, p. 168 
intacta 2-8 =2/3 of 7 =2/3 of 8 =2/5 of 8 =3/5 of 9 Ndm. ’01, p. 517 
glacialis 2-8 =1/2 of 7 =1/3 of 8 =1/3 of 8 =1/2 of 9 Ndm.’01, p. 518. 
proxima 2-8 =1/4 of 7 =1/5 of 8 =1/4 of 8 =1/3 of 9 Walk. ’16, p. 420 
hudsonica 2-6 0 0 =1/3 of 8 =1/4 of 8 Walk. ’14, p. 275 
borealis 2-6 0 0 =1/2 of 9 =1/3 of 9 Walk. ’16, p. 416 
* Dorsal hooks in relation to length of segment bearing them. 
** Lateral spines in relation to length of segment bearing them. 
This holartic genus is represented in our fauna by half a dozen 
species that may be separated as follows: 
KEY TO THE SPECIES (exclusive of borealis) 
Adults 
1 Middle abdominal segments (4-7) with pale middorsal triangles 
PD eS, ORS IGE TRL BO? GE CES eee | hudsonica, p. 241 
Middle abdominal segments black: 2 oF) PP. Tr ee 2. 
2 Abdominal segment 7 with twin dorsal spotsof yellowintacta, p. 242 
Abdominal segment 7 with no twin dorsal spots of yellow..... 3. 
3 Sides of thorax heavily clouded, not streaked... .glacialis, p. 243 
Sides of thorax with at least 1 distinct fuscous stripe (stripe 5) 
Men ete SOE sk Aas tec cs oc rg «cate teh are frigida, p. 243 
TENS oo PIN oe ees ce: Ae ee ee ee ee proxima, p. 244 
224. Leucorrhinia hudsonica Selys 
Selys ’50, p. 53: Mtk. Cat. p. 166: Ris ’12, p. 718: Howe ’20, p. 84: Garm. ’27, 
p. 282. 
Length 27 mm. Expanse 46 mm. N. B. to Alask., B. C. and N. H. 
