54 THE CANADIAN ENTOMOLOGIST. 



the tooth on the inner margin of the superior claw will be over- 

 looked; it is very faint, scarcely perceptible in some cases. The 

 type specimens of Isotoma Walkerii appear to be lost. There 

 is nothing in the description of Walkerii to hinder its being 

 united with Isotoma leonina. The only definite characters 

 given in the description of Walkerii are a comparison of the 

 lengths of the segments of the antennae Specimens that are 

 undoubtedly leonina, and compared with the types of that 

 species, do not differ from the description of Walkerii. A 

 very common species under the bark of recently felled trees. 



Habitat— Massachusetts (Packard) ; Ithaca, New 



York ! Walkerii, Pack. 



26. Tibiae without tenant hairs ; superior claw without teeth on the outer 



margin, and a single tooth on the inner margin ; inferior claw 

 with a tooth on the inner margin ; mucro with three teeth — the 

 first forming a blunt, subhorizontal, obliquely rounded end ; the 

 second and third of the same length, about as long as the 

 mucro is wide ; the third tooth in a higher plane than the 

 second ; furcula not attaining the ventral tube ; dentes longer 

 than the manubrium ; body black, paler at apices of the seg- 

 ments ; antennie dirty white ; legs and furcula white ; antennpe 

 as long as the head. Habitat — Salineville, Ohio. .obsoleta,x\.%'^. 



Tibiifi with tenant hairs 27. 



27. Mucro with three teeth — the first long, distant from the second, and 



making a distinct vertical hook ; the second of the same length 

 as the first, vertical, and in the same line ; the third smaller 

 than the second, and not in the same line ; furcula attaining the 

 ventral tube ; dentes twice the length of the manubrium ; 

 superior claw without teeth on the outer margin, and a single 

 tooth on the inner margin ; inferior claw greatly dilated at base, 

 dilation squarely interrupted at middle, and with a distinct 

 tooth on the outer angle of the dilation ; tibiae with two tenant 

 hairs ; body and antennae black, paler at the juncture of the 

 segments ; legs dirty white, blackish at base ; furcula white ; 

 antennce slightly longer than the head ; a bristle at the apex of 

 the dentes extends beyond the apex of the mucro. Habitat — 

 Dover, Massachusetts (A. P. Morse) determinata, n. sp. 



