Q Department Circular 294, U. S. Dept. of Agriculture. 
As in the case of the infestation of buildings by rats, the mites 
were to be found in both modern concrete and old frame and brick 
structures. 
The mite troubles seem to have been confined to buildings in the 
business sections of the city rather than to residences. Only one 
report of the mite in a residence reached the writer, and this build- 
ing was not far from the business section. It is possible that the 
mite may have been introduced into the business section and that it 
has failed to become generally distributed over the city, or that the 
dwellings have afforded less opportunity for the uninterrupted 
breeding of rats. LZxamination of a number of rats, including their 
young and nests, in one residential section failed to show the presence 
of this mite. In the main business portion of the city the distribu- 
tion was found to be extensive, reports being received throughout al- 
most its entire length. One building devoted to business in a resi- 
dential section was reported infested. This was located 24 miles 
from the nearest known infestation in the main business district. 
As to the character and size of the buildings known to be in- 
fested, it has been mentioned already that there was considerable 
trouble from the mite in buildings of thoroughly modern construc- 
tion. This should not be construed as meaning that there is not a 
distinct advantage in this type of construction, for it makes possible 
the control of both rats and mites, whereas in old structures with 
considerable lumber in their make-up, thorough control is almost an 
impossibility without extensive overhauling and improvements, 
A number of the reports of mite trouble came from department 
stores. The pests occurred in various departments and often were 
well distributed among the clothing, hosiery, bolt goods, etc. Some 
reports came from grocery stores, one from a railroad general-oflice 
building, one from a motion-picture theater, and one of the most 
troublesome infestations was in a music house located in an old 
structure adjacent to two restaurants where rats were known to 
abound. The Federal buildings in both Dallas and Fort Worth 
were infested. 3 
The mites gave trouble on all floors of the buildings, from the 
lowest to the highest; one of the buildings investigated was 10 stories 
high, and the mites were present on the top floor. 
It appears that the existence of suitable hiding and nesting places 
for the rats is a greater contributing factor in mite annoyance than 
the temporary presence of many rats while feeding. 
LIFE AND HABITS. 
Little definite information has been gained concerning the habits 
and life history of the mite. All of the infestations investigated by 
the writer show the mites to have been associated with the brown rat 
(Rattus norvegicus). Mr. Hirst records it from Lf. norvegicus, LK. 
rattus, and Acomys cohirinus. Judging by the freedom with which 
it attacks man, there seems little doubt that it would feed on various | 
species of rats and mice as well as other warm-blooded animals. 
The comparatively few mites found on the bodies of rats when 
running about away from their burrows indicates that the mites feed 
largely on the young or adult rats while they are quiet in their nests" 
