342 Notes and Comments. 
RATS. 
Part XIX. of ‘A History of British Mammals’ has been 
published,* and deals with the Black or Ship Rat, the Brown 
or Common Rat, and the House Mouse. Each species is dealt 
with in the careful and thorough manner which has charac- 
terised this work throughout. We learn that ‘ extraordinary 
calculations have been made as to the damage done by rats 
and the rate of their increase. F. von Fischer calculated that 
a single pair might leave, after ten years, a progeny of 
48, 319,698,843,030,344,720 rats. Mr. Lantz calculates that 
in nine generations, a single pair of rats would, if breeding 
uninterruptedly, produce more than twenty million individuals, 
but such a calculation is entirely theoretical. However, as 
he states that the average quantity of grain consumed by an 
adult or half-grown rat is fully two ounces daily, or 45 to 50 
Ibs. a year, the average cost of feeding one rat for a year 
becomes about seven shillings and sixpence.’ 
MORE RATS. 
From the October number of The Scottish Naturalist we 
learn that in a communication by Oldfield Thomas, on the 
generic names Rattus and Phyllomys, the author confesses 
his disappointment at the discovery that the name Rattus was 
used earlier than he anticipated for the ordinary Rats, and, 
therefore, has priority over Epimys, which he hoped would 
be accepted. As a consequence, his ‘ attempted use of Rattus 
for Azara’s Spiny-rat fails, and this animal will have to bear 
in future the burden of Euryzygomatomys as its generic name.’ 
Poor creature ! 
MODERN ‘ ENTOMOLOGY.’ 
The Entomologist’s Monthly Magazine for October is a 
mixed bag. Mr. D. Sharp says, ‘I adopted Mulsant’s name 
of consimile for this species, being under the impression that 
it and Mulsant’s mollis would be found to be mixed in some 
collections, and that Mulsant was authorised to apply the name 
of mollis to either of the two forms. I have, however, found 
no example of his mollis in any collection I have examined.” 
Another ‘ correction’ is given in the next paper by Mr. G. C. 
Champion, who overlooked a description of Batobius when 
dealing with this genus. But our entomological friends should 
not overlook things, and then have to make corrections after 
giving wrong names; this sort of thing is becoming ‘ chronic,’ 
and is a distinct hindrance to scientific work. Of a more 
satisfactory nature is Mr. R. S. Bagnall’s establishment of 
Trioza proxima as a British insect (in Sunderland), and Mr. 
H. S. Wallace’s record of a new British gall-midge, Mayetiola 

* Gurney & Jackson, pp. 601-648 (plates), 2s. 6d. net. 
Naturalist, 
