TAXONOMY OF TROMBICULIDS 
147 
Subgenus Trombicula Berlese 1905 
including subgenus Neotrombicula , Worn. 1952, partim. 
Type. — Trombicula minor Berl. 1905 1155, Redia, 6, 346-388. Genotype; adults only from bat-guano, 
Java. 
Provisional Diagnosis (restricted). — Larvas without the combinations of characters of the other 
subgenera; scutum not broadly rectangular, but more nearly quadrate or trapezoidal, posterior margin 
convex (scutum almost bluntly pentagonal) or emarginate and medially convex (sinuous); sensillary bases 
fairly close together (SB less than 2/3 AP); no long nude setae on legs; parasitic on mammals (type is a 
very small species presumably parasitic on bats.) Nymphs & Adults of typical Trombicula facies, without 
eyes (type adult very small). 
Remarks . — The probable relationships of T. minor have already been discussed. The 
writer is well aware that the diagnosis given above is based on tenuous concepts. Its object is 
to prevent the subgenus from being used too freely as a depository for unallocated species, 
the writer preferring to leave such species unallocated sub judice. Until something better is 
found the writer proposes to take the new Malayan bat-chigger which has been bred to the 
nymph (fig. 2) as a model around which to frame this subgenus. There are good reasons to 
suppose that it is congeneric with minor. By adopting a model which can be described in 
detail in both larva and nymph, it will at least be possible to build up a consistent subgenus, 
even if it may later prove to be the wrong one (which however is most unlikely). 
Those species known only from the adult and listed by Womersley under Neotrombicula 
should be held unallocated until they can be surely placed in Trombicula , Neotrombicula , or 
another subgenus; the cavernicolous species in particular may belong to Trombicula. These 
species are : Camilla , cavernarum , clavicata , coarctata , formicarum , manriquei , moesica , }russica 
Vitzthum, 1932 (not Ouds. 1902; this adult cannot be identified with either russica or muscae 
and its name may be homonym, but it might as well be left as it is for the time being). 
Microthrombidium minutissimum Ouds. 1910:104 ( Ent . Ber. } Amst ., 3, 103-109) from a bat 
in South Africa, has been redescribed by Fuller (1952:86) and we may note those characters 
which may be of subgeneric importance: small chiggers with a small scutum (AW 30-45 u. or 
less) which is nearly as deep as broad. AM advanced in front of line of ALs (anterior margin is 
triangular in minutissimum). Sensillae simply forked (or ? with very few subequal barbules). 
The advancement of the AM seta may readily be exaggerated in this particular chigger (cf. 
species of Doloisia sens, lat., p. 157) and it probably cannot be regarded as a subgeneric 
character even though in this species it gives a very distinctive inverted-pentagonal shape to the 
scutum. Allowing for this, the peculiar forked sensillae and the general shape of the scutum 
suggest a relationship with the bat-chigger T. batui. There also appear to be close relationships 
with T. munda and with several African chiggers related to T.panieri Jad. & Verc. 1952, viz., 
giroudi , panieri , & rodhaini , as well possibly with T. schmitzi (which has barbed sensillae). 
Speleocola Lipovsky 1952 was raised to accomodate a peculiar chigger ( S . tadaridae) from 
the ears of molossid bats in Oklahoma. The edges of the scutum are obscured by 
the attachment of cuticular striae, and the somewhat fusiform sensillary shafts are clothed in 
expanded setules which gives the sensillae an appearance of being lanceolate. The relations 
of this very interesting genus to T. spicea should be investigated. 
Because the writer has yet had no opportunity to make a careful study of them, the 
species listed below are offered only as suggestions for investigation. The fist includes a 
number of bat-chiggers, which is an interesting coincidence because the species have not been 
chosen for their host preferences. 
Old World Species (tentative). — Europe: minutissima. Africa: ? T.panieri group ( cynictia , giroudi , 
panieri , rodhaini ). Also 7 mastomyia, No. CORU36696 n. sp. (in harrisoni- group; bat, S.W. Africa). 
Asia & Pacific: batui , }insolli , minor A, munda , piercei , ?schmitzi; T. harrisoni group (all from bats — dimolinae, 
harrisoni N , R17289 n. sp. Malaya). ?T. spicea group — }buxtoni , }khurdangensis , rajoriensis, spicea. 
MALA YA , No. 26 , 1953 
