144 3 - R- AUDY 
Some of the many anomalies resulting from this grouping under the broad “ post-larval ” 
subgenus are noted below: 
(i) Species fordi , hastata , and traubi, with foliate or otherwise peculiarly modified 
dorsal setae, are not properly separable from Trombiculindus which is recognised 
as a subgenus by Womersley (see p. 141 above). 
(ii) The writer would ascribe the larvae of goldii and scincoides, as well probably as those 
of kohlsi and tovelli , to subgenus Eutrombicula (= subgenus Trombicula, Worn. 
partim). Similarly larvae of sarcina would be thus accomodated, because of 
their close relationship with larvae of samboni ; but the nymphs and adults of 
samboni appear to be typical Eutrombicula ( Trombicula of Womersley) and those 
of sarcina typical Neotrombicula. Wharton & Fuller (1952:47, 48) list goldii 
and sarcina under subgenus Eutrombicula ; but they also include coarctata, 
known only from the adult. 
(iii) The larva of jayewickremei appears to be inseparable from those of some members 
of the subgenus Leptotrombidium sensu lato. 
(iv) As described elsewhere (Traub & Audy, 1953, this Study p. 48 ), there is a distinct 
group now recognisable related to T. densipiliata Walch. The nymphs of one 
member of this group are very close to that distinctive species canestrinii , known 
only from the adult. But the larvae are obviously different from those of the 
type, autumnalis. The same applies to such species as spicea and members of 
the harrisoni-g roup, which have larvae quite unlike those of autumnalis but have 
nymphs included in Womersley’s broad subgenus. 
(v) Womersley has also described the nymph of Heaslipia gateri and states that this 
cannot be distinguished clearly from nymphs of his subgenus Neotrombicula. 
(vi) Species such as T. flagellifera Traub & Audy 1953 and T. tuhana Traub & Audy 
3:953 (pp. 46,53,55), have leg setae suggestive of Neotrombicula but their scuta 
and to some extent their palpal setation resemble those of Leptotrombidium spp. 
It may be that many or even most of the species included in the broad subgenus by 
Womersley on account of post-larval characters should in fact be included in the subgenus 
Trombicula as provisionally redefined in the present paper. This course was not open to 
Womersley because he interpreted the existing drawings of T. minor as definitely showing the 
presence of eyes. As we have suggested, this interpretation may readily be a mistaken one. 
The present writer is not prepared to resolve any of these difficulties. It does however appear 
that the broad subgenus based on post-larval characters is not wholly natural. There may of 
course be convergence of polyphyletic groups of larvae in one direction, and of their 
corresponding postlarval stages in another, but this has not yet been demonstrated. 
It would appear to be a sound step at this stage to recognise a true subgenus Neotrombicula 
sensu stricto, including only those species which are clearly related to the type in both larvae 
and nymphs, and to divide Womersley’s remaining species into two groups, (a) those which 
appear to have sufficiently close affinities with minor to be included provisionally in the subgenus 
Trombicula pending further studies, and (b) those which cannot confidently be relegated to 
either group but which have affinities with both on the characters of nymphs and adults. This 
last group may be provisionally considered as ? Neotrombicula or ? Trombicula and in the lists 
of Old World species given by the present writer he has attempted to relegate certain species 
to one or other subgenus on fairly arbitrary larval characters. He does this without much 
confidence, but in the belief that this is one more step in the right direction. 
At the same time, as many small species-groups as possible should be recognised. This 
has been done for the subgenus sensu stricto by Brennan & Wharton (Joe. cit.) who have 
STUD. INST. MED RES. 
