182 First Annual Report 
follows: The two stout bristles on each side of the posterior part 
of the abdomen arise from tubercles which are situated at the end 
of the abdomen, which, while bifureated, is not as pronouncedly so 
as in the other females. I have traced the outlines carefully with the 
camera lucida of all the tips of abdomens, male and female and as- 
sembled them, according to sex, with reference to their center lines. 
The variation of outline thus shown in Figure 98, is not pronounced 
enough to include the outline of this other, ynusual form. In 
the latter, anal suckers are present, and the arrangement of the 
chitinous plates running up toward the genital opening from the sides 
of the abdomen, is strikingly different. Length of this single speci- 
men, 400 micrm. Width, 143 micrm. Since this specimen occurred 
Figure 101. Copidognathus curtus 
on the same bird with the others of the species just described, it is 
probably best to consider it as an aberrant form of the same species. 
As this species does not agree with the generic description in regard 
to the bifureated condition of the abdomen in the female, this varia- 
tion just described, in which the bifurcation is not so marked, may 
indicate a transition form. 
Copidognathus californicus n. sp. 
(Figures 99 and 100) 
Length of body, 610 micrm. ‘‘Sehnabelteil’’ not apparent (prob- 
ably very short). First two pairs of legs stouter than the others but 
not greatly swollen. Armor not very strong. Eye-plates irregular 
