492 PROCEEDINGS OP THE NATIONAL MUSEUM. vol. 50. 



105) large, with four unequal peripheral tubercles. Antennae shorter 

 than the head; segments in relative lengths as 5:4:5:6; fourth seg- 

 ment with seven olfactory hairs: two outer, two inner, and three 

 dorsal (fig. 106). Sense-organ of third segment as in figure 107. 

 Between the third and fourth antennal segments is a large ventral 

 eversiblo bilobed sac (fig. 108). Body stout; abdomen feebly dilated. 

 Unguis (fig. 109) long, slender, slightly curving, unidentate near the 

 middle of the inner margin; lateral margins each unidentate one- 

 fourth from the base (fig. 110). Unguiculus with suboblong basal 

 lamella and setaceous apex, extending about as far as the tooth of the 

 opposite claw. One long tenent hair, unknobbed. Dentes stout, 

 subcylindrical. Mucrones (figs. 111-113) half as long as dentes, api- 

 cally rounded ; inner lamella narrow, simple; outer lamella with a large 

 subtriangular dorsal lobe. Anal spines (figs. 114-116) long, a Httle 

 longer than the ungues in adult specimens, slender, curving, on large 

 contiguous papillae, which are one-third to one-half as long as the 

 spines. Clothing (fig. 117) dense, consisting of abundant short curv- 

 ing setae and numerous long hairs and setae, which are frequently 

 serrate. Length, 1.5 mm. 



In small specimens the anul spines are shorter than the ungues and 

 straight. One of my specimens had three fully developed anal spines, 

 there being an accessory median spine in front of the other two ; this 

 variation occurs in several species of the genus. 



The two following varieties have been found in Europe but not as 

 yet in this country: var. inermis Axelson ('056), in which anal spines 

 and papillae are absent; and var. cuspidatus Axelson ('056), in which 

 the seta of the unguiculus extends almost beyond the unguis and is 

 bent distally. 



Specimens from the United States agree with European examples, 

 as both Dr. Schaffer and myself have found. 



The cotypes of Achorutes loletivorus Packard ('73) in the Museum 

 of Comparative Zoology, Cambridge, Massachusetts, are A. armatus 

 Nicolet. Those that I studied there were labeled "Brunswick, Me., 

 Sept. 10;" the specimens recorded by Packard from Salem, Massa- 

 chusetts, being absent from the collection. 



The cotypes of Achorutes marmoratus Packard ('73) were also 

 missing; but Packard's description of this species evidently applies 

 to the lilac-colored variety of A. armatus that I used to find in abun- 

 dance in eastern Massachusetts. 



Packard's ('73) description of Achorutes texensis also applies to 

 A. armatus so far as it goes. The cotypes of texensis consist, however, 

 of two specimens of armatus and four of another species of Achorutes, 

 short-spined and apparently undescribed, which can not be fully 

 described at present without sacrificmg some of the cotypes. I hope 

 to got some more specimens of this speciec from Texas. 



