246 PKOCEEDINGS OF THE NATIONAL MUSEUM vol. loi 



and twisted on its longitudinal axis; it possesses membranous mar- 

 gins and is much wider than fixed chela. All maxillary and palpal 

 setae smooth. Length-width ratios of tarsi of legs are: Leg I 6:1, 

 leg II 4 :1, leg III 6 :1, leg IV, 8 :1. All setae on legs are smooth. 



Male. — Dorsal shield covers entire dorsal surface; setation as in 

 female. Tritosternum and presternal area as in female. Ventral 

 shield not covering entire ventral surface; expanded posteriorly to 

 lateral margins of coxae IV; tapering gradually to a point in the 

 anal region ; bearing sternal, metasternal, usual, and accessory genito- 

 ventral setae and usual and accessory anal setae. Setae like those of 

 female in size and position. Sternal pores as in female. Peritreme 

 and epistome as in female. Chelicerae as in female except that prox- 

 imal seta of fixed chela is lacking. Absence of sexual dimorphism is 

 distinctive. Maxillae and palpi as in female. Relative size and seta- 

 tion of legs as in female ; femur, genu, tibia, and tarsus of leg II each 

 possess a conspicuously heavy ventral seta on tarsus with a thick prox- 

 imal and slender distal portion. Length- width ratios of tarsi are: 

 Leg I 6 :1, leg II 4 or 4.5 :1, leg III 6 :1, leg IV 9 :1 or 10 :1. 



Nymfh. — Dorsal shield narrower that in female; setation as in 

 adults ; tritosternum and presternal area as in adults. Sternal shield 

 with sternal and metasternal setae. Usual genitoventral setae flank 

 posterior end of shield ; setae as in adults in relative size and position, 

 except that middle pair of sternal setae are on lateral margins of 

 shield. Anal shield as in female but with only three usual and five 

 anteriormost accessory setae; as in adults the posterior usual setae 

 is largest on shield. Metapodal shields and ventral setation as in 

 female. Peritreme not well developed. Epistome as in adults, but 

 with fewer fimbriae, most of which are branched. Chelicerae, maxil- 

 lae, and palpi as in adults. Relative size and setation of legs as in 

 female. 



ReTTiarks. — Distinctive characteristics of E. liponyssoides that serve 

 to distinguish female, male, and nymph from those of other species 

 are : Female : All setae smooth ; lacinae of tritosternum smooth ; pre- 

 sternal sutures with spines; posterior margin of sternal shield in- 

 vaginated to level of midpoint between posterior and middle pairs of 

 sternal setae ; genitoventral accessory setae between 19 and 41 in num- 

 ber ; in most specimens between 21 and 26 ; mean number 23.5 ; 7 acces- 

 sory setae on anal shield ; posterior usual anal seta largest on shield ; 

 shape of peritreme distinctive; epistome with 7 to 10 usually simple 

 lateral fimbriae on each margin, and four or five branched distal 

 fimbriae ; both chelae toothless ; a seta at proximal end of fixed chela. 

 Male : Dorsal shield covers entire dorsal surface ; setation as in female 

 except on leg II, on which femur, genu, tibia, and tarsus each possess 



