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J. R. AUDY 
The most comprehensive accounts of the taxonomy of the trombiculids are the excellent 
and timely monographs published during 1952 by Womersley, by Wharton & Fuller, and by 
Fuller. Wharton, aided by Fuller, has published an invaluable manual, the taxonomic part 
of which had however to be completed immediately before a spate of new species were described 
and without access to Womersley’s simultaneous studies of the postlarval stages. Womersley, 
in a taxonomic compendium, has described and redescribed some 230 species from the Asiatic- 
Pacific area. He has also made an outstanding contribution to the study of the postlarval 
stages of trombiculids from the world, but this is a pioneer work and the study of this subject is 
still relatively undeveloped: only 56 out of some 520 species of larvae have been correlated with 
the nymphs or adults. Fuller has made a meticulous study of type material in Holland and 
has added opinions gained from his considerable experience. A number of other workers — 
such as those involved in the Kansas Chigger Project — are engaged in intensive work on 
trombiculids and they will certainly be making considerable taxonomic contributions. 
A large amount of material from Malaya — over 30 new species with 20 nymphs — has been 
studied but not described, and unpublished bionomic data have accumulated. In addition, 
over 15 undescribed species and 13 undescribed nymphs have been collected in North Borneo 
(by joint research teams in collaboration with Traub and with the financial support of the 
Surgeon- General’s Office, Washington, U.S.A.), and in Sarawak (in collaboration with Tom 
Harrisson of the Sarawak Museum). It is very unfortunate that some of the more important 
material came to light too late to be made available to the above authors. It will be several 
years before the new material can even be described. Although discussion of much of the 
superficially studied material is premature, the writer believes that at this stage a useful and 
worth-while appendix can be given to the three monographs already published, so that workers 
may draw upon some of the Malaysian material in interpreting them and perhaps in dealing 
with their own taxonomic problems. The writer is aware that he is laying himself open to 
heavy criticism for some of the prematurely published opinions ; nevertheless, the sound council 
of withholding opinions until they mature may be better for one’s reputation but in this 
particular case it would not be helpful. The taxonomy of the trombiculids is still unsettled 
even at subfamilial and generic levels, and it must be made clear that the object of this paper 
is to offer data and a few tentative opinions based on the Malaysian material so that fellow- 
workers can use them as they see fit in clarifying the taxonomy of these mites. It offers four 
things: comments on the taxonomic significance of certain characters; some bionomic 
information of taxonomic interest; provisional revised definitions of genera and subgenera 
given in the light of the material studied in Malaya over the last five years ; and lists of Old 
World species more or less up to date (early 1953). In order to make the publication more 
compact and the text easier to scan, authors have been omitted except where there might be 
confusion, and the trivial names are freely used without their generic initial; the species 
concerned are those listed by Wharton & Fuller followed by Womersley (who added many 
new species). 
The Taxonomic Importance of Various Characters 
The various genera and subgenera have apparently been raised in three different ways. 
Firstly, a genus may be raised on a useful key-character, by which we mean characters, such 
as the presence of teeth on chelicers, which are convenient for the construction of artificial 
keys ; but these genera have a habit of becoming more and more painfully artificial and sometimes 
also of accumulating species which are not congeneric — this most commonly happens because 
it is difficult for the taxonomist not to come to look upon specimens as chitinous patterns on 
slides, rather than as living creatures. An example is the genus Schongastia (p. 150). 
Secondly, a monotypic genus may be raised to accommodate a species with outstanding 
characters. If it does not remain monotypic, then it is often found that the genotype is not 
STUD. INST. MED. RES. 
