°6 PROCEEDINGS OF THE NATIONAL MUSEUM VOL. 120 
Labidocera. Within north-south limits of the diandra range, L. 
detruncata was very rare and decidedly offshore; L. acutifrons was 
abundant chiefly in the more offshore tows from blue, highly trans- 
parent water; and L. acuta was the numerically dominant species of 
the genus in blue to bluish-green water especially within 10-20 miles 
of the coast. Wherever the latter two species were abundant, diandra 
was rare or absent. The abundant catches of diandva were made in 
green to greenish-blue, relatively turbid water. 
REMARKS ON IDENTIFICATION.—Adults of diandra are distinguished 
from other species, except jollae and kolpos, by (1) partial fusion of 
segments 8 and 9 and separation of 6 and 7 in the nongeniculated A1; 
and (2) the short robust rostrum in which the base of each prong is 
swollen in lateral and frontal views. 
Adult diandra are easily separated from kolpos and jollae by the 
absence of head-hooks. 
The male is further characterized by (1) the terminal segment of 
the left P5 lacking prominent spines, hooks, or modified setae; (2) the 
right Al with segment 18 bearing a proximal process overlapping at 
least the entire length of segment 17, superficially as in L. aestiva, but 
differing in that abutting surfaces of the process and segment 17 are 
rounded and the joint separating segment 17 from 18 is not hinged as 
in aestiva superspecies (for aestiva superspecies, see Giesbrecht, 1892, 
pl. 23, figs. 3, 4); and (3) the asymmetry in P3 and P4 of Sel on Re2. 
In the female, excellent identifying features are found in dorsal 
view in (1) the combination of the lateral spinous process extending 
laterad from the right side of TV; and (2) the lateral, hooklike process 
extending from the left side of the genital segment. 
Remarks on Spermatophore Placement and Mating 
About 36 percent of adult females carried spermatophores (table 4). 
A number of females carried more than one, arranged in a variety of 
combinations of type 1 and type 2 placements. Some carried more 
than one spermatophore of the same placement, the couplers being 
arranged in sequence, one on top of the other, the sacs lying parallel 
to one another. 
Type 1 was the most frequent and geographically widespread 
spermatophore placement observed. In this position the neck is in 
close proximity to the genital pore although the actual point of con- 
tact is obscured by the sheath. The less frequent type 2 occurred 
sporadically and the mouth of the neck is not in contact or even in 
close proximity to the segment, the coupler and neck being cemented 
to the left corner of TV. 
In the material at hand, the frequency of type 1 spermatophore 
placement was more than three times that of type 2, and the latter, 
