Tarsonemidce 
69 
They often attack people working in poultry houses or handling and 
plucking infested fowls. They may cause an intense praritis, but they 
do not produce a true dermatosis, for 
they do not find conditions favorable for 
multiplication on the skin of man. 
Tarsonemidae 
The representatives of the family Tar¬ 
sonemidae are minute mites, with the body 
divided into cephalothorax and abdomen. 
There is marked sexual dimorphism. 
The females possess stigmata at the 
anterior part of the body, at the base of 
the rostrum, and differ from all other mites 
in having on each side, a prominent clavate 
organ between the first and second legs. 
52 ' P ma^ loi AfLr V Webs C t°er US ’ fe " The l arva > when it exists, is hexapodous 
and resembles the adult. A number of the 
species are true parasites on insects, while others attack plants. 
Several of them may be accidental parasites of man. 
Pediculoides ventricosus 
(fig. 52 and 53) is, of all the 
Tarsonemidae reported, the 
one which has proved most 
troublesome to man. It is a 
predaceous species which 
attacks a large number of 
insects but which has most 
commonly been met with by 
man through its fondness for 
certain grain-infesting insects, 
notably the Angoumois grain 
moth, Sitotroga cerealella, and 
the wheat straw-worm, Iso¬ 
soma grande. In recent years 
it has attracted much atten¬ 
tion in the United States and 
its distribution and habits 
have been the object of detail- 
W,, T_/ _ \ 53. Pediculoides ventricosus, gravid female. (X SO) 
Study by Webster (1901). After Webster. 
