
A REVISION or rox MICROTROMBIDIINAE (ACARINA, 
TROMBIDIDAE) ov AUSTRALIA ann NEW GUINEA 
By H. WOMERSLAEY, FLREAS., ATS, Exromecocisr, Sourn Ausrratran Museu. 
Fig. 1-38. 
in the Zool, Anz, 1935, 109 (1/2), 107-112, Sig Thor in reviewing the family 
Trombidiidae, divided i1 into ten subfamilies, the sixth of which he ealled the 
Ofteuiinae, with the genus @é/ania P. Kramer, 1877 (as emended by G. Canestrini, 
\. B. George and himself) as the type. Later in the same publication (1935, 110, 
(1/2), 47) he changed the subfamily to Mierotrombidiinae with Microtrambidium 
(+. Tlaller, 1882, as type, on the grounds that O/fonia was preoceupied by Gistel 
1848, in the Crustacea and by von Malm, 1875, in the Vermes. 
Jn the Records of the South Australian Museum 1937, 6, (1), 75-LOD, the 
present writer reviewed the ther: knowu Australian species of Trombidiidae in 
the light of Sig Thor’s studies, 
Since-that tine much more material has come to hand, meluding some from 
New Guinea, and a further revision of the family is needed. In the present paper, 
however, only the subfamily Mierotrombidiinae is dealt with and that only 
as fur as the adults or nymphs are concerned, the larval stages being very little and 
inadequately known, 
The genus Microtrombidium Haller was first split by Berlese (Redia, 1912), 
into Mnremothrombium anc Microltrombidium s. str, the lather with two sub- 
renera Dromeotlrambium and Mieroltrambulaum, on the structire of the dor- 
gal setae, Lnomothrombiym beme restricted to a heterogeneous lot of species with 
very variable types of dorsal setae but all of which differed from the simple, more 
or less pennate type found in Microtrombidium and Dromeathrombium. 
Tn 1916 A, Krause (Zool, Auz., 47, 97, fig. 1-6) erected from the Rivemo- 
thrambivm complex, the genus Campylothrombinm for those species in which the 
dorsal setae were of uniform length, clavate, septate and decumbently curved. Sig 
Thor in 1936 (Zool. Anz. 114, 30) went a stage further and placed Berlese's M. 
perhigerum, in Which the setae are uniformly short and tree-like with intertwin- 
ing branches, in a new genus Dendroltrombidium. M. vagabundum (Berl, 1903) 
he mace the type of Flalytrombidium tigen. in Which the dorsal setae are short, 
flat and broad, generally triangular and pointed, and fusiform with fine ciliations. 
He included here several other species, For M. pexatwm (Koch, 1837) (= caly- 
cigerum Berl, 1910) he ereeted the genus Camerotrombidium, in which the larger 
Horsal setae wt least, were erect, globose, septate and chambered, generally short 
und papilliform, In this genus he ineluded C. collinum (Hirst, 1928), simile 
(Hirst, 1928), and first? (Wom,, 1984) all from Australia. 
In 1987 Womersiey (Ree, 5, Aust. Mus., 6, (1), 83) erected the genus Fehino- 
thrombium, with O. spnosum. Canest., 1877, as type, for those species in which 
some or all of the dorsal setae are spine-like with or without short eiliations. In- 
cluded here were several Australian species, Berlese's M, (#.) eutrichum was, in 
the same paper, tiade the ype of a uew genus Butricholthrombiwm in which the 
dorsal covering consists of closely packed, globose, non-septate setae, interspersed 
with longer fine setae, A new genus Lamimothrombium, with the dorsal setae as 
uniformly short, pointed, leaf-like laminae with strong mid-rib and marginal 
cihations, was made fora new Anstralian species Lo myrminun, Amonpat thegenera 
