CIRCULAR No. 118. 
Issued April 23, 1910. 
United States Department of Agriculture, 
BUREAU OF ENTOMOLOGY, 
L. O. HOWARD, Entomologist and Chief of Bureau. 
A PREDACEOUS MITE PROVES NOXIOUS TO MAN. 
(Pediculoides ventricosus Newport.) 
By F. M. Wesster, 
In Charge of Cereal and Forage Insect Investigations. 
INTRODUCTION. 
While the scientific and medical literature of European countries, 
and to some extent of Asiatic countries, contains numerous records 
of mites attacking man, it is difficult to determine, from a perusal 
of this literature, whether or not the mite 
Pediculoides ventricosus Newport, shown in 
its most active form by figure 1, has been 
concerned in these attacks. There is no 
particular reason why it should not have 
become noxious to man precisely as, and 
elsewhere than, in America, because it has 
doubtless, with its host insect, the Angoumois 
grain moth, Sitotroga cerealella Oliv. (fig. 3), 
been distributed in grains throughout the 
warm regions of the globe, wherever these 
grains have entered into international com- 
merce. While there is a decided similarity 
between these attacks on man in Europe and 
America, the writer is unable to select, from 
the various instances recorded, a single one in 
which he can unhesitatingly say that this and 
not some other species of mite was responsi- 
ble for such attacks. In many cases it is very 
clearly to be seen that other and very differ- 
Fie. 1.—Adult female of Pedicu- 
loides ventricosus, before the ab- 
domen has become inflated with 
eggs and young. In this condi- 
tion the mite is nomadic and 
predatory. Greatly enlarged. 
(Redrawn from Brucker.) 
ent species of mites have been involved in attacks of a similar nature, 
both in this country and in Europe. Here-in America such troubles 
[Cir. 118] 
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