222 



THE MYRIAI'ODA OF NORTH AMERICA. 



would apply probably equally well to several species. In the absence of any type, it has 

 seemed better to apply the name somewhat empirically, rather than to discard it alto- 

 gether. 



As far as I can determine, P. Virginiensis of Sanssure is not the species here recognized, 

 but represents rather the two species trimaculatus and corrugatus combined, both of 

 which he appears to have had. 



I lob. Middle States. 



Pig. 50 



I'. CORRIHIATIIS. 



I\ atro-castaneus, seutis fulvo postice marginatis; latmois lateralibus fulvis, latissimis j scuto anale triangulare, 



elongate, postioo fulvo, apicc trunoato ; appeodieibus masculis maximis, spinulo laterals vobusto subbreve vix 

 curvato armatis; spina, terminate maxima, robusta, compressa, tortuosa, spinulo basalo arniata. (Fig. 50.) 



Blaokish-ohestDUtj scuta margined with fulvous posteriorly; lateral lamina; yellowish, very broad; anal scutum 

 triangular, elongate, posteriorly yellowish ; its apex truncate; male appendages very large, armed with a rather 

 short, robust, scarcely curved, lateral spinulo; terminal spine very large, robust, compressed, tortuous, armed with 

 a basal spinulo. 



P. CORRUGATUS, Wood, Proc. Acad. Nat. Soi., 1864, p. (j. 



The color of the perfect animal is a chestnut-black, rarely reddish chestnut, with a 

 moderately broad margin of fulvous [in alcoholic specimens] on each scutum. This band 



may he red during life. The scutai beautifully polished to the 

 naked eye, the microscope shows to be obsoletely wrinkled. Very 

 many of these wrinkles are longitudinal. Tin; head is of the same 

 color as the body; medianly it is distinctly sulcate ; interiorly it is 

 broadly and rather deeply cmarginate. The scutal side plates are 

 fulvous above and below. Their anterior angles are rounded, their 

 posterior more or less acute, and in the hinder ones prolonged. 

 The under surface of the body is of a light yellow. The male 

 genital appendages are very large and robust. They have a short, slightly crooked spinule 

 attached and lying close to their side. The terminal spine is irregularly spiral, and lias 

 near its base a curved spinule. At .the point of its origin is a tuft of bristly hairs. Each 

 female appendage (Fig. 51) is chiefly composed of a short, almost globular, scarcely at 

 all pilose process, in one side of which there exists a large opening. Through the side 

 opening projects a pair of large, thick plates, fitting together somewhat in the man- 

 ner of bivalve shells. These nearly equal in height the main process. The spine on 

 the second joint of the feet is robust, but acute. The whole animal is about one and a. 

 half inches in length. 



Hub. Michigan.— Prof. Miles.— Trenton Falls, New York. Mus. Comp. Zoology.— T). Mack. 



