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PACIFIC SCIENCE, Vol XVII, April 1963 
tensions are cup-shaped and form socket-like 
attachments for the fourth legs. The division be- 
tween the fourth pedigerous segment and the 
genital segment is distinct and curved convexly. 
The shape of the female genital segment (Fig. 
12/) is variable, dependent upon the number 
of eggs present in the segment. The segment is 
flaccid and ovoid in females that have recently 
extruded egg strings, and is almost circular in 
females whose genital segment is packed with 
eggs. Two small knoblike protrusions are pres- 
ent on the posterior margin lateral to the junc- 
tion of the abdomen; these knobs are charac- 
teristic for the female of this species but are 
not present until the adult stage. The general 
shape of the fifth legs is similar to that of the 
sixth chalimus although the proximal seta of 
the three plumose setae present on the lateral 
surface of the leg of the preceding stage now 
arises from the surface of the genital segment, 
just lateral to the base of the fifth leg. The 
movement of this seta may be due to the swell- 
ing of the genital segment. 
The genital segment of the male (Fig. 12k) 
is ovoid, the width slightly more than three- 
fourths the length. The shape of this segment 
and of both the fifth and sixth legs is very simi- 
lar to that of the sixth chalimus male. The ar- 
mature of the legs of both stages is identical. 
The abdomen of the adult female and male is 
slightly longer than that of the sixth chalimus 
(0.12 mm average for 15 sixth chalimus speci- 
