148 J. R. AUDY 
Unallocated species of Trombicula 
An attempt has been made to collect the remaining species into as many species-groups as possible. 
There is no doubt that many more groups will be discovered by further study. The groups presented are 
mostly tentative and have not been investigated deeply. Attention is drawn to the Trombicula cynos 
group described by Brennan (1952): many more studies like this are badly needed in this region. 
anous-group : anous, pluvius. 
geckobia-group (Asia & Pacific; almost pentagonal scutum, on reptiles; see p. 146): incurva , geckobia , 
gymnodactyla, ?naultini, pentagona. 
ilesi-group (Africa; pentagonal scutum; on reptiles; may be related to Fonsecia , see below): aenigma , 
homopholis, ilesi , montensis, nivaria, rhodesiensis , rhoptropi ; ? frittsi (Malaya, Australia), 
lawrencei-group (Africa; Prelated to geckobia-group, see p. 146): lazvrencei, draconensis , gerrhosauri , 
pachydactyli. 
leveri-group (bats): leveri , revelae. 
muscae-group (bats; p. 141): muscae, philipi, quadriense , taphozous. 
parmifera-group (almost pentagonal scutum, on reptiles): parmifera , lundbladi , “MAB” n. sp. in MS. 
rara-group (AW:SB about 5-6:4; on reptiles, arthropods): rara, n. sp. nr. rara from pill-millipede 
(Worn. & Audy in MS) ; ? 7thori. 
vorca-group (mostly on birds): }corvi, }canestrinii, densipiliata , nissani , tstrinatii, vorca Traub & Audy 
1953 (this Study p. 48) (& thompsoni Brennan from U.S.A.). 
Ungrouped species. — Europe: clavicata A, formicarum A , moesica A, vernalis , willmanni W. & F. 
( = multisetosa Will.), zachvatkini. Africa: boaedonia, bruynoghei, centropodis , claviglia , claviglicola, 
guineense, jadini, microps, nigeriensis, praomyia (p. 160), rhodesiana , scapulosa, sicei , subquadrata , 
sulae , tragardhi. Asia & Pacific: ablephara , consueta N, jayewickremei N (p. 141), jubbulporensis 
(see p. 160), kalrae , southcotti, vietzi; agamae Andre. 
Genus Fonsecia Radford 1946 
Type. — Trombicula ewingi Fonseca 1932:153, Mem. Inst. Butatan S. Paulo , 7, 151-158. From a 
snake, Brazil. 
Diagnosis . — Trombiculines of the Trombicula group whose larvae have at least the anterolateral 
scutal setae (ALs) modified by reduction to peglike or short expanded processes; scutum shield-shaped, 
roughly as broad as deep, bluntly pentagonal; parasitic on reptiles, possibly exclusively on snakes. 
Remarks . — A new species from Malaya is being described (Audy 1955, in MS) in which 
the modification of the setae is carried on to involve the PL setae and the anterior rows of dorsal 
setae as well. The AL setae are peculiarly modified in a way suggestive of those of 
F. travassosi Fonseca. The PL setae and anterior dorsal setae are modified more simply by 
basal swelling, like the setae of Euschongastia causicola (Jadin & Verc.). This group is 
sufficiently distinct in both morphology and host-preference to be recognised as a genus. It 
appears to be closely related to the ilesi group (T. ilesi itself also being from a snake) and indeed 
the two groups may later prove to be congeneric. 
The modification of these setae is extremely interesting. There are very many examples 
to show that the PL scutal setae and the anterior dorsal setae are genetically finked and develop 
under the influence of the same organiser (using this term in the embryological sense). When 
setal modifications in this PL-DS field are extensive, they may involve the AL setae also, but 
rarely the AM. The genus Fonsecia illustrates modification of the other organiser field, the 
ALs alone being modified in ewingi & coluberina , and both ALs & AM in travassosi , while 
the extensive modification in the new Malayan species secondarily involves the PL-DS field in 
producing a less developed modification of those setae, while the AM seta is unmodified. A 
study of the many chiggers with foliate setae shows that modification in the PL-DS field does 
not usually extend to those post-and para-anal setae which we describe as “ caudal setae ” 
(CS), where presumably the influence of the VS-field is felt. Similarly, the humeral setae 
(HS) which often differ from the dorsal setae in both larvse and nymphs, appear to be influenced 
by the coxal field (we may note the tendency for multisetose coxae to be associated with multiple 
humeral setae, e.g. in Doloisia sensu lato, p. 157). 
STUD. INST. MED. RES. 
