22 
found of value. Where more vigorous treatment is necessary the meas- 
ures recommended for the ox-louse may be adopted. 
SUCKING LICE INFESTING THE RODENTS. 
(Hannatopinus sp.) 
Belonging to the same genus of suctorial lice as those previously 
mentioned, we have a number of species common to the smaller mam- 
mals, particularly those of the group of gnawing mammals, the Rodentia. 
These smaller mammals, though perhaps never strictly domesticated, 
save the rabbit, are very often kept in a semi-domesticated state, either 
as pets in zoological gardens or, in case of rats and mice, quite involun- 
tarily because of our inability to entirely rid ourselves of them. A few 
notes on the lice infesting them will therefore be of interest here. Itis 
desirable to be able to identify them in case of their accidental occur- 
rence on other mammals, and thus to be able to determine whether, in 
such cases, we have to deal with a species likely to prove of any trouble. 
The common rat {Mus decumanus) supports a species, Hcematopinus 
spinulosus, which with its host must be distributed over most of the 
world. It has been taken at Ames, Iowa, though in small numbers, and 
it seems to be rather scarce. It is not recorded heretofore for this 
country so far as we know, and many animals were examined before 
finding specimens ; a fact in part due, perhaps, to its minuteness. 
It is a small species of a light yellow color, the head projecting very 
little in front of the autennre and the thorax very short. The mice are 
said to harbor a distinct species, but there seems to be some doubt as 
to its being a genuine species. 
Hccmatopinus acanthopus occurs on the field mice and has been taken 
at Ames from a species of Arvicola. It resembles the preceding in 
color and form, but is somewhat larger; the egg presents somepeculiar- 
ities, which are described in detail in the appendix. 
Other species described in European works are the H. sphcerocephalus 
on Sciurus vulgaris, audi/". Iceviusculus on Spermophilus eversmanni, and 
two species, H. lyrioceplialus and H. ventricosus, on rabbit or hare. 
These have not been met with as yet in this country. 
Specimens have been taken from our common flying squirrel, fox 
squirrel, ground squirrels, and chipmunk, and also from the white-footed 
mouse and the pocket gopher, which do not appear to have been previ- 
ously described, and these will be found described in detail in the ap- 
pended note. 
THE ELEPHANT LOUSE. 
{Hcematomyzus proboscideus Piaget.) 
This louse, infesting the elephant, is about as exceptional in its 
way as the animal which harbors it. It appears to be of quite recent 
notice, though it is not unlikely that it has been known in countries 
