406 
PACIFIC SCIENCE, Vol XI, October, 1957 
In both Centrotromhidium and Diplothrombium 
the basifemur and telofemur are completely 
separated by a flexible synarthrodial mem- 
brane. The femora of the adults of all species 
are divided. 
Specialized Setae of the Appendages 
Here it is well to digress a little in order to 
point out a difficult situation which exists in 
the nomenclature of the specialized setae of 
the appendages of the Parasitengona. In the 
United States the majority of the work in the 
terrestrial Parasitengona has been done in the 
Trombiculidae, by investigators whose major 
or even sole interest in the group was stimu- 
lated by the medical or general parasitological 
importance of these mites. In no case is there 
any published evidence that these workers 
have availed themselves of Grandjean’s stud- 
ies on the types of setae found on the append- 
ages of mites in general including the Parasi- 
tengona. Grandjean’s unexcelled contributions 
to the chaetotaxy of the Acari began in 1935 
and have continued up to the present time. 
The major setal types were clearly elucidated 
and named prior to 1940. Grandjean’s studies 
were cilmaxed in 1947 with the publication 
of his Etude sur les Smarisidae (1947) in which 
the broad outlines of the morphology of the 
various setal types on the appendages of the 
Parasitengona were laid down. This was one 
of the classics of modern acarology and it is 
incomprehensible that certain workers should 
have proposed a "standardized terminology’’ 
of the trombiculid mites, including the spec- 
ialized setae, without a single reference to 
this or Grandjean’s numerous other publica- 
tions. It is to be hoped that acarologists 
generally will realize that it is definitely not 
in the best interest of acarology for any group 
of workers to set up a highly formalized and 
(by virtue of the number who have contrib- 
uted) ostensibly authoritative system of ter- 
minology, either in complete ignorance or in 
complete disregard of the intensive work of 
others who have devoted many years of pro- 
found study to the morphology of the Acari. 
The Trombiculidae are no more than one very 
small segment of the Acari, and there is no 
reason why they should be treated differently 
from other groups, despite the medical im- 
portance of a few exceptional members of the 
family. 
In his studies on the Johnstonianidae, the 
writer has followed the system of nomencla- 
ture proposed by Grandjean, first in 1935, 
and expanded in subsequent years. This will 
inevitably cause confusion to those familiar 
with only the terminology proposed by 
American workers (Wharton et al ., 1951). 
This is not done on the basis of priority, but 
with the knowledge that a choice must be 
made between two systems, plus the convic- 
tion, based on experience, that the older 
Grandjean nomenclature is more universally 
applicable, more fundamental, and, in the 
final analysis, more logical and comprehens- 
ible than the newer highly specialized ter- 
minology promulgated by investigators whose 
experience in the Acari is either primarily or 
entirely limited to immature stages in a single 
family. 
The following table of equivalents is pro- 
vided to help in the transposition from one 
system to the other. 
Many examples could be cited to show 
the inevitable difficulties in the setal termin- 
ology which has sprung up during the past 
few years. One of these difficulties stems from 
the fact that the terminology has been evolved 
almost exclusively as an outgrowth of the 
describing of larvae and shows gross incon- 
sistencies when an attempt is made to apply 
it to postlarval stages. A second is that related 
setae are often given quite different names, 
while some totally unrelated setae are given 
confusingly similar names. 
For instance, the "subterminala” is a spe- 
cialized seta found near the tip of the tarsus 
of leg I and the palp. In the adult the onto- 
genic descendants of the "subterminala” of 
the palpal tarsus are called "apical setae” or 
"apical nude setae.” The morphological de- 
