PEACH. ROOT SPECIES OF PORCELLIO. 121 



o. 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 tpecimen than after death. 



b. multrguttatus. A row of smaller whitish spots along the middle of the back 

 between the yellow ones. Common. 



c. margiiiatus. The hind margins of the segments pale or whitish. 



d. lateralis. The outer fourth part of each segment whitish with a black spot 

 therein. 



c. limbalis. The spots of var. d confluent forming a black stripe with a brown or 

 blackish spot on each side of each segmeut outside of the stripe. 



It is difficult, in short, to find two individuals of this species which are alike in 

 every re-spect. 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 Pokcellio (P. scaber, Latreille). Blackish lead-colored often varied 

 with irregular blotches of whitish, the surface roligh from numerous elevated points 

 which are arranged in irregular transverse rows. Length 0.46. This is much mora 

 rough and the elevated points more acute than in either of the furegoiLg 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. 



