138 
J. R. AUDY 
Remarks. — The type species is unknown in the larval stage, while its description in the 
adult stage is very incomplete. The type specimens, from a bat-cave in a remote part of Java, 
were destroyed by the bombing of Hamburg during the war. Dr. Cornelius B. Philip in 
March 1948 approached Dr. A. Diakonoff of the Zoologisch Museum en Laboratorium at 
Buitenzorg (now the Museum Zoologicum Bogoriensis, Bogor, Indonesia), but attempts to 
collect some more material in the type locality failed. Dr. Diakonoff has since been appointed 
to the Rijksmuseum at Leiden. The present writer recently attempted to get more material 
collected, but in a letter dated June, 1953, Dr. A. Lieftinck, Director of the Museum at 
Bogor, explains that “ there are still difficulties in getting to the Tjiampia caves and I fear that 
there will be no chances of this at all since I have been informed that the bat caves at this 
locality are entirely spoiled, the fauna having disappeared almost completely. So there is no 
particular reason to visit the spot again, except for a pilgrimage. Since, as far as I know, there 
is no one in Indonesia working on Trombiculids at the moment, practically none of the former 
rich bat cave localities being at all accessible, I am afraid that I should not succeed in getting 
specimens for you from elsewhere.” 
Willman (1941) gave a redescription of the type together with drawings of part of the 
scutum and palps. Unfortunately there was at that time very little material available for 
comparison, so that the re description is incomplete in the light of post-war studies. It is 
also important to note that the drawing of the parts of the scutum which Willman wished to 
discuss is semi-diagrammatic. Gunther (1951) has given a valuable review of the early des- 
criptions of minor , and its later temporary confusion with the scrub-itch chigger T. wichmanni. 
We know that T. minor is a very small species (adult about the size of most nymphs), and 
that being recovered from bat-guano the larvae are perhaps more likely to be found on bats than 
other animals; while we have an imperfect drawing of the scutum and palps, and meagre 
descriptions of features which are not of generic importance. The writer wishes to comment 
on two problems : the interpretation of the existing drawing and description of the type, and 
the best way of handling this difficult genus. 
Womersley (1952:328) interprets the relatively large circles around the sensillary bases of 
T. minor (fig. 2) as being eyes which have been displaced so as to he behind the sensillary 
bases. In this he differs from Ewing (1944) who believes that the circles represent chitinous 
rings. On this assumption Womersley erected his subgenus Trombicula which is in fact based 
on the post-larval characters of T. wichmanni and other species of Eutrombicula. The present 
writer doubts Womersley’s interpretation of Berlese’s and Willmann’s drawings for the 
following reasons : (a) the bilateral symmetry argues somewhat against distortion and 
displacement; (b) taking the actual small size of the scutum into account, the “ sensillary 
bases ” as drawn are relatively much too small because these structures do not vary greatly in 
size as does the scutum generally; (c) the overlap between the edges of the sensillary bases and 
the intervening part of the scutum is taken by Womersley to be evidence of displacement of 
both sensillary bases and the “ eyes ” and so also is the eccentric origin of the sensillae 
themselves ; but such a partial overlap may often be seen in specimens where the intervening 
sensillary area is convex, while even if there is displacement this still does not suggest the 
existence of eyes ; and the eccentric origin of the sensillae is quite commonly seen ; (d) the larvae 
of species which have been associated with minor in possessing eyes in the postlarval stages are 
bird and reptile chiggers (here treated as subgenus Eutrombicula) quite unlike any chiggers 
so far recovered from bats in this region; (e) three species of Trombicula now known from bats 
are very small, but not one resembles Eutrombicula ; (/) two species of nymphs examined by 
the writer (fig. 2) show a sufficiently close resemblance to the drawing of minor to suggest 
that the larger circles drawn from type material are the rims of the sensillary bases and not 
STUD. INST. MED. RES. 
