(dr. a. c. otidemans). notes on acari. 123 



1875. Brady's CJieijletus robertsoni apparently is our friend, 

 though it «was dredged off Hawthorn, on the Durham coast, in a 

 depth of 27 fathoms,» where it may have arrived after a fatal fall 

 off from any water fowl; or it floated on the surface and sticked 

 to the dredge when it erose from the unknown depths; or it was 

 accidentally in the conservation- tube. 



1876. Van Beneden, without giving any description, presents 

 us a new drawing, possibly re[)resenting our Ch. erudiius. 



1876. Kramer treats the mouth parts, possibly of the same 

 species. 



1877. Canestrini and Fanzago give a description too short to 

 recognize the species. Possibly it was Ch. eruditus 



1877. MuRHAY tells us only what Kocii, Fumouze, Robin and 

 Beck observed of the animal's habils. 



1880. MÉGNIN, without any description presents us a new drawing, 

 possibly representing Ch eruditus. 



1881. Kramer publishes the results of his examinations on the 

 development of a Cheletes, probably Ch, eruditus Schrank. 



1886, Cheyletus eruditus of Berlese seems to me to be the 

 same species, but the situations and the number of the hairs, and 

 the shape of the posterior shield are wrongly represented. 



1886. Canestrini's diawing of a real eruditus misses thedoi-sal 

 shields and hairs. 



1893. Berlese tell us: «in mari rima genitalis omnino in medio 

 dorso aperitur» which is only the case in some Chelitidae, not in 

 the genus Cheletes, however. 



Frotonympha. Length, (fig. 34), 400 — 480 .u. — Colour pale. 

 Shape well known. Texture smooth in the shields, finely wrinkled 

 in the unprotected parts. — Dorsal side protected by an anterior 

 shield, which is trapezoidal, wider posteriorly, slightly longer than 

 wide, and provided with 5 pair of hairs. In the posterior half of 

 the dorsum there are 5 pairs of hairs, first a row of 4, and then three 

 pairs one after another. The hairs are very narrow feathers (fig 36). 



Feutrai side (fig. 35) coxae 1 and 3 with 2 hairs each, coxae 

 2 with 1 hair, coxae 4 bare. Between coxae 2 one pair; in the 



