r212 NEW YORK STATE MUSEUM 



The first and second abdominal segments much reduced. The 

 outer fourth of the anterior margin of the third abdominal seg- 

 ment on each side is contiguous with the posterior margin of 

 the last thoracic segment. The epimera of the third, fourth 

 and fifth abdominal segments are successively more curved 

 posteriorly and their margins continue the oval outline made 

 by the lateral margins of the thoracic segments. The sixth 

 abdominal segment is triangular in shape with a broadly 

 rounded apex forming the terminal margin. Lateral margins 

 concave toward the middle lines. 



The outer terminal branches of the uropods are flattened 

 plates, lateral to the terminal abdominal segment, and com- 

 plete the oval outline of the body posteriorly. 



Of the abdominal appendages the first two pairs are provided 

 with tracheae. 



The features most distinctive of this species are 1) the promi- 

 nent frontal lobe of the head, subrectangular in its dorsal 

 aspect, 2) the sixth abdominal segment of the shape above 

 described, and 3) the large outer terminal branches of the 

 uropods which are of a general oval shape but subtruncate on 

 the anterior and inner lateral margins. 



As very little has been published about the distribution of 



the land isopods in this country the following notes of the 



species occurring in the locality of Schenectady may be of 



interest: 



Porcellio rathkei Brandt 



This is the commonest species. It is the one to which the 

 common name of wood louse most appropriately applies, as they 

 are always found on decaying wood, under the bark and in the 

 crevices of logs, stumps, and under boards, etc. about dwellings. 

 They vary very much in color. For diagnostic characters of 

 this and the following species see tables in the American 

 naturalist, May 1900, or Key to the isopods of the Atlamtic coast of 

 Nm^th America, by Harriet Richardson, published as pamphlet 

 no. 1222, Proceedings of the U. S. national museum, Washington 

 1901. 



