88 
Psych e 
[June 
on the tarsi of acarid mites and has thus been able to 
simplify their description. 
In the trombiculid mites four types of modified setae 
are found on the legs and palps as follows : 
1. Blunt striated sensory setae — one on the dorsal side 
of each tarsus of the first two pairs of legs and 
one at the base of the palpal tarsus on the ven- 
tral surface. 
2. Pointed striated sensory setae — on the genua and 
tibiae of all leg, the tarsus of leg I, and the pre- 
tarsi of legs I and II. There may be on one tar- 
sus III and the palpal tarsus, hut this is unusual. 
3. Microsensory setae — may be present on the genua, 
tibiae, and tarsi of legs I and II. 
4. Whip-like setae — one or more may he present on telo- 
femur, genu, tibia, and tarsus of leg III. 
Unfortunately these setae are not all constant in their 
positions on the legs but may vary from species to species. 
It is therefore impossible to name them on the basis of 
location. One solution to the problem is to name the 
fixed setae while reserving fluid terms for the others. The 
following system is suggested. 
spur = blunt striated sensory seta on the tarsus. (The 
use of the term spur for this seta is adopted 
from Brennan 1947, Ewing in many papers 
has referred to this seta as the dorsal spine, 
but since it is usually rounded at its tip, 
Brennan’s term is to be preferred.) 
pretarsala = the striated sensory seta on the pretarsus, 
subterminala = the pointed striated sensory seta on the 
dorsal prominence of tarsus I. 
(The term subterminal is taken 
from Ewing 1931.) 
parasubterminala = a microsensory seta associated with 
the subterminal seta. 
microspur = a microsensory seta close to the spur or 
situated between the spur and the snb- 
terminal seta. 
tibiala = a pointed striated sensory seta on the tibia, 
microtibiala = a microsensory seta on the tibia. 
