1932 ] Nomenclature of the Moss-mites 61 
editions or reprints and therefore of no systematic or bio- 
logical interest, and one is A earns plantarum Mayer 1781 
which Oudemans considers a synonym. 
Acarus plantarum Mayer is not a typical Nothrus because 
the abdomen is described as “at the breast somewhat com- 
pressed, broader and round towards the hind region.” If 
it were N. biverrucatus or a related form, the subparallel 
sides and especially the two horned posterior end would 
have been mentioned. The color characters recall a nymph 
somewhat like that of H. bistriata Michael (1888, pi. 42, fig. 
9— but this is “eyeless” !) . Certainly it is not an adult, for 
even the legs are alternately grey and black ! 
Acarus geniculatus Linne 1758 
(Oudemans, part I, pp. 348-353; part II, pp. 775-782.) 
Under this head Oudemans marshals about 55 references 
(to 1805) many of which being non-binomial, later edi- 
tions, translations and compendiums do not concern the 
systematist. Nine, however, were distinctly published as 
original descriptions of formerly unrecognized species, 
namely, those of 1665, 1668 (see pt. 2, p. 775), 1764 Linne 
(=1758), 1752, 1763 Scopoli, 1776 Schrank (=1781), 1778 
DeGeer, 1799 Rathke, 1800 Shaw. Of these, those of 1665, 
1668 and 1752 are not binomial scientific names, and only 
Linne’s is a genotype ! Are these really all synonymous ? 
I cannot determine from these descriptions what resem- 
blance A. lichenum Scopoli has to A. geniculatus. It is from 
Carniola (Krain, Austria), not Utrech, Holland. 
A. musci Schrank 1781 (described in greater detail in 
1776) from the figure looks like still another species and 
also comes from Austria. It will probably be many years 
before this species can be properly reidentified. 
A. corticalis DeGeer 1778. Presumably Oudemans ex- 
pects us to identify this species with the species figured by 
him in part I, p. 351. This can hardly be done because (1) 
DeGeer’s species is shining (not punctured), (2) there is a 
distinct depression across cephaloprothorax between inser- 
tions of legs I, (3) the long bristles on legs are not on apex 
of tibia, (4) there are more abdominal hairs than in Oude- 
mans’s figure. As stated before (Jacot 1929g, p. 417, last 
paragraph), I consider DeGeer’s Acarus corticalis as en- 
