51 
The above generic definition has been drawn up from quadrangula and 
does not agree in some of the minor details with the characters of margar - 
itacea. Clemens Sm. shows no difference in genitalia from quadrangula 
and a specimen from the Barnes collection which has been compared 
with Smith’s type agrees in maculation with our Labrador and Alberta 
series of quadrangula; it is imagined that, at the best, clemens can only be 
regarded as a race of this species. 
Chersotis Bdv. 
1840, Gen. et Ind. Meth, 103 (type, rectangula Schiff.). 
Male Genitalia. Clasper broadening suddenly in central portion and 
then narrowing gradually to the rounded apex; no corona; sacculus strong 
with a heavily chitinized elbowed free arm at base, this arm being spined 
apically and spiculate over a considerable portion of the dorsal surface; 
harpe very heavily chitinized, broadly scoop-shaped, projecting over costa. 
Clavus absent. Juxta weak. Uncus long and thin. Tegumen with ventral 
margin broadly truncate, not pointed as usual. Aedoeagus strengthened 
apically with a triangular chitinous plate. 
Figure 30. Male genitalia of Chersotis juncta Grt. 
Very similar to the preceding genus in outer structural characters and 
differentiated solely on account of the male genitalia and the fact that our 
North American species, juncta Grt., is very closely allied in all respects 
to the European rectangula Schiff., the genotype of Chersotis. The avail- 
ability of this generic term has led the writer to adopt it for the present, 
but the whole group with this peculiar type of basal arm to the sacculus 
will have to be studied in connexion with European species before deciding 
whether one generic term is sufficient; juncta is the only North American 
species with this type of genitalia. 
