1894.] Notes on a Species of Simocephalus. 397 
In all characters not mentioned, this form agrees with 8S. 
vetulus, Mueller. Whether the above differences can be explained 
by omissions and oversights by observers is not known. The 
sharp angle of the posterior part of the body, the caudal sete, 
the reticulations of the shell, the plumose basal joint of the 
antenne and the three joints of the third ramus of the superior 
antenne are enough to characterize a new species near S. vetulus 
Mueller. I have a supply of alcohol and glycerine specimens, 
or can get living specimens another season, and will be pleased 
to send them to any one who has authentic specimens of 
Simocephalus vetulus, Mueller, for comparison, as I reluctantly 
make a new species of this form, never having seen S. vetulus, 
Mueller. We will be pleased to receive specimens of S. vetulus, 
Mueller from any one who has them. ) 
Specimens varied in size from 1.5 mm. to nearly 3mm. 
Below is given measurements of a good sized specimen. 
Measurements. Total length 2.67 mm. Total breadth 1.47 
mm. Head from end of beak to where it joins the shell above, 
‘785 mm. Sup. ant. .667 mm.—ratio of joints 10-1-4-3}-3}. 
Inf. ant. 140s, including spines at the end—long spine in 
front 90u.—terminal sete 332. Eyes 107». d. Claws at post. 
end of body 3mm. — 
Two sete at post. part of body .88 mm. 
Terminal setz of ant. .59mm. Reticulations on side of shell 
35 apart. Plumed sete on interventral margin 115x. Third 
ramus of sup. ant. 115y, ratio of joints 2:5:7. Longest spine 
in front of anus 80». 
EXPLANATION OF PLATE. 
Fig. 1.—Simocephalus species showing the general outlines of 
the female. (Original.) : 
Fig. 2.—The young immediately after birth, showing the 
two-lobed eye and the basal joints of the antenne. 
(Original.) 
Fig. 3.—The posterior part of the abdomen showing the 
angle back of the anus and the posterior sete. 
(Original.), 
