TWO SPECIES OF PARASITIC MITES. 337 
cure. Sulphur ointment applied repeatedly to the diseased parts is 
said to effectually destroy the pest. A solution of Balsam of Peru 
in alcohol, applied carefully, has also been highly recommended. 
PsoRERGATES SIMPLEX, N. G. & SP. 
While engaged in the study of Sarcoptes minor, 2 mouse was 
brought to me which had a crusty scab on the lower part of the 
back of the ear, extending round its outer edge and into the interior 
of the conch, where it assumed the appearance of a tough, leathery 
skin of a dirty grey colour. When a piece of this scab was pulled 
off with the forceps and placed under the microscope, a number of 
small mites were seen crawling over and burrowing their way into 
it. At first sight they appeared to me very much like small, short 
specimens of Myobia musculi, but a more careful study showed them 
to be separated by many marked characteristics from this latter 
species. It was seen, too, that they were all males, and that a fur- 
ther search must be made for thefemales and young. I therefore 
placed the scab in glycerine and tore it to pieces with needles, and 
in this way brought to view a number of round, white specks, which 
proved to be the females, nymphs and larve, resembling the male in 
very little else but the structure of the rostrum and the even distri- 
bution of the feet along the sides of the body. 
This is in all probability the species mentioned by Gerlach, in a 
book entitled ‘ Kritze and Riude,” published in 1857, as occurring 
on the ear of the common mouse, though on this point I am unable to 
speak positively, as I have had no opportunity of seeing the original 
description and figures. As M. Megnin, however, in his invaluable 
work on ‘“‘ Les Parasites et les Maladies Parasitaires,” says that it is 
impossible to determine from the original figure even to what family 
this mite belongs; and as neither Megnin, in the book just cited, 
nor Gerstiicker, in his review of Gerlach’s work in “ Archivs fiir 
Naturg eschichte,” make any mention of a name having been given 
to it, and as Fiirstenberg in his extended synopsis of Krédtze and 
Réude does not even notice the fact that an itch-mite had been 
recorded from the mouse, it seems advisable to publish a new 
description of it and give it aname. If it appears afterwards that 
it has already received a name, the one now used will of course be 
abandoned and the previous one adopted in its stead. 
