J 910.] NATURAL SCIENCES OF PHILADELPHIA. 379 



Neuropodial setae mostly concealed above by the felt, arranged 

 in the usual three series, the dorsal being stout and deep brown and 

 two or sometimes three in number, the middle paler, about half as 

 thick and four or five, the ventral yellowish brown and much more 

 slender and more numerous, ten being almost invariably present 

 on middle segments. As compared with most similar species setae of 

 all three series are long and slender and shaped more nearly like those 

 of A. Jiamata than any other species. All are nearly straight — those 

 ( >f the ventral series (Pi. XXXII, fig. 81c) most curved — perfectly smooth 

 with no trace of hairyness or tuberculatum and with a slight subter- 

 minal enlargement tapering to a slender acuminate tip, the last two 

 characters also much more accentuated on the ventral setae (figs. 81a-c). 



Notopodium bearing two series of large setae (PI. XXXII, figs. 79 and 

 80) the ventralmost or lateral arranged in a nearly vertical series of 

 six to eight which pass through the felt and then bend sharply dorsad 

 with their slender ends resting upon it. The dorsalmost group is 

 irregular and usually consists of six to eight setae more or less dis- 

 tinctly in two short rows which penetrate the felt obliquely and rest 

 upon it more or less concealed in the covering silt. All of these setae 

 are dull brown, soft of texture, longitudinally striated, quite without 

 surface asperities, stout and flat at the base and tapered to slender 

 ends with hooked tips. The apical sheaths sometimes present are 

 unusually long and are free of hairyness (fig. 80). Seta of the ventral 

 series are shorter and more abruptly tapered, the dorsal more gently 

 tapered and reaching beyond the middle of the body, increasing in 

 length from before backward. The capillary fibers have the usual 

 arrangement into dorsal, intermediate and ventral tufts. The former 

 are confined to elytrophorous segments and are very abundant, forming, 

 with the intermediate tuft, the dorsal felt, the individual fibers being- 

 very long and slender with hooked tips. The ventral tuft forms the 

 iridescent plumes and the fibers are short, coarser, somewhat rigid, 

 tapered to very fine straight points and are very smooth so that no 

 foreign matter adheres to them. 



Toward the head the arrangement of the notopodial setae becomes 

 simplified by the merging of the two groups of notopodial setae and 

 two groups of fibers. Neuropodial setae become longer and more slender 

 and on III and II, the ventral series is replaced by a dense patch of deli- 

 cate bipinnate setae (PI. XXXII, fig. 82). In this group the dorsalmost 

 setae are longest and coarsest and bear a short pennant-like tip. Pass- 

 ing toward the ventral side this tip increases in size at the expense of 

 the remainder of the setae and becomes spirally turned until on the 



