6l8 IVAR teagArdh 



Ventral side (fig. 146). The sternal shield is very little darker than 

 the other shields and has no sculpture; it is slightly longer than it is wide in 

 the middle, on a level with the 2nd pair of bristles, and the posterior margin forms 

 an even curve forwards, extending to the middle of coxae III, with blunt pos- 

 terolateral angles. There are two pairs of large, transverse, slit-like pores, one 

 closely behind bristle I, the other halfway between bristles II and III. The 

 sternal hairs are of the same length. 



Metasternal shield narrow, widening backwards, extending from the 

 middle of coxae III to a little beyond the middle of coxae IV, with one pairs 

 of hairs, as long as the sternal hairs. 



Geniti-ventral shield with the genital part apparently set off from the 

 rest by a straight, transverse furrow, tongue shaped and with numerous longi- 

 tudinal, slightly radiating striae. 



Ventral part broad, with rounded sides, posteriorly with rounded incision, 

 where it is contiguous with the anal shield, ^/a as long as it is wide, without 

 any sculpture. There are 4 pairs of pointed bristles placed as fig. 146 shows. 

 Since Berlese in his latest description lays much weight on the distance be- 

 tween the bristles I have measured this: I 178 \l, II 304 \i, III 400 {i, IV 285 [i. 



The legs (fig. 146). Coxae I with two stout bristles, the posterior one of 

 which is twice as long as the anterior one; coxa? II — IV with the usual stout 

 bristle. The legs do not exhibit any remarkable features. 



Mouthparts. The epistome I have not been able to see plainly; the 

 hypostome does not exhibit any characteristic features. The mandible (fig. 

 147): lower jaw strongly curved at the top, with large terminal tooth behind 

 which there are two conical teeth, close together; upper jaw shorter and 

 more slender than lower jaw with more slender terminal tooth and further back 

 two broad, rather short teeth. 



Loc: Juan Fernandez. On Rattus rattus; numerous females. 



25. Urobovella bicarinata n. sp. — Figs. 148 — 157. 



This species is through its peculiar shape, blunt anteriorly, pointed pos- 

 teriorly, and through its polished cuticle and strongly arched dorsal shield sufficiently 

 well characterized as belonging to the genus Urobovella Berl. It is true that 

 there is no distinct dividing line between the ventral and anal shield in the 

 present species which in this respect does not agree with the original diagnosis 

 of the genus given by Berlese (Acari nuovi. Manipulus I. 1903, p. 249) 

 which is as follows: » Scutum anale a metapodies seiunctum». But, on the other 

 hand, BERLESE already in 1904 somewhat altered his views as to the import- 

 ance of this feature. In the key which he gives of the genera of the fam. 

 UropodidcB (p. 325) he writes: »Linea metapodiea nulla (Metapodium integrum, 

 totem ventrem occupans, vix a scuto anale seiunctum). And in his diagnosis 

 of the genus (1. c. p. 336) he writes: »Anus plerumque in scuto suo lato, linea 

 plus minusve Integra (in U I pan data evanida) transversa, ano propinque a scuto 

 ventrale distincto*. 



