825 
No. 145.] 
a. dorsalis. The space between the rows of yellow spots of a deeper black color 
than other parts of the body, forming a broad black stripe along the middle of the 
back. This stripe is much more obvious in the living specimen than after death. 
b. multiguttatus. A row of smaller whitish spots along the middle of the back 
between the yellow ones. Common. 
c. margiaatus. The hind margins of the segments pale or whitish. 
d. luterulis. The outer fourth part of each segment whitish with a black spot 
therein. 
e. limbalis. The spots of var. d confluent forming a black stripe with a brown or 
blackish spot on each side of each segment outside of the stripe. 
It is difficult, in short, to find two individuals of this species which are alike in 
every respect. Still, the species is in all instances readily distinguished by its sculp¬ 
ture, the raised granules occupying the hind marg.ns of the segments although they 
are less elevated here than upon the disk. In all our other species having the surface 
granulated, these margins are smooth. 
The Rough Porcelmo (P. scaber, Latreille). Blackish lead-colored often varied 
with irregular blotches of whitish, the surface rough from numerous elevated points 
which are arranged in irregular transverse rows. Length 0.46. This is much more 
rough and the elevated points more acute than in either of the foregoing species. I 
have not met with it in this State. Specimens sent me from Ohio by Dr. Robert H. 
Mack, and from Illinois by R. W. Kennicott, differ in no respect that I am able to 
perceive from European individuals of this species. 
