April, > 18 ] 
EWING AND HARTZELL: CHIGGER-MITES 
259 
ferent birds and mammals. Oudemans has compiled a list of fourteen 
determined host species. To this should be added a larger list of hosts 
that were only determined to the genus or family. The species is 
reported from England, France, Belgium, Holland, and Germany. 
The Striated European Chigger 
[Thrombidium striaticeps Oudemans] (Fig. 106) 
There is another chigger-mite of Europe known to attack man and 
domestic animals. It does not appear to be as common or as impor¬ 
tant a pest as the two just considered. This chigger has parallel stria- 
tions on the dorsal shields or plates. The larvse are egg-shaped, and 
when somewhat swollen with blood are about 0.5 mm. in length. 
This chigger has been found on man, the dog, the cat, and the domes¬ 
tic fowl. Its normal hosts are for the most part dipterous species. It 
has been reported from France, Belgium, and Holland. 
The Kedani Mite 
[Microthrombidium sp.] 
In certain parts of Japan there is a chigger-mite that has been asso¬ 
ciated with a fatal disease known as river fever or flood fever. Tanaka, 
especially, insists that there is a connection between these mites and 
this disease. It appears that the mites by their attacks produce 
lesions which become points of entrance for certain bacteria which 
are the real cause of the fever. At the point of attack there is a papule 
which becomes surrounded by an inflamed area. This is followed by 
a pustule which gives way to a black scab. 
The mites concerned are orange-red, and measure about 0.2 mm. in 
length when not engorged. The palpi are strong and single clawed. 
The legs are stout, and each is provided with three tarsal claws, the 
middle one being longer than the rest. The femora are divided. 
Above, the body is clothed with about thirty long doubly pectinate 
hairs. 
The kedani mite appears to be a Microthrombidium species accord¬ 
ing to Tanaka’s figure. Yet he does not show some of the more impor¬ 
tant taxonomic characters. The adult form is unknown. 
The Ceram Chigger 
[Microthrombidium wichmanni (Oudemans)] 
Two chigger-mites are found in the East Indies that according to 
the various but authentic reports of different travelers must cause a 
scourge which is far more severe than any caused by the species of 
the temperate zones. One of these mites, it appears, is the species 
