293 
Notes on the Uroyodinse. By A. D. Michael. 
previously by Latreille, in 1829, for a genus of Coleoptera, also by 
Gravenhorst in the same year (1829) for a genus of Hymenoptera, 
also by Bell in 1862 for a genus of Crustaceans ; and Trachinotus 
bad been used by Lacepede and subsequently by Cuvier in 1817 for 
a genus of fishes, besides the frequent use of Nototrachus, &c. 
Although Kramer’s name cannot be maintained, his creature may 
well be the type of a separate genus, and the distinction upon which 
he founded it, viz. that the excavations in the ventral plate for the 
reception and protection of the legs when folded, which exist in most 
other Uropodinae, are absent in this genus, ought to be, and is pre- 
served ; although later discoveries have shown that the species without 
excavations require more than one genus. The genus Dinychus was 
added by Kramer in 1886 ; the other existing genera have been all 
added either by Canestrini, Berlese, or Thorell, The table of the 
second author, at p. 87 of his e Ordo Mesostigmata,’ published in 1892, 
is practically the only general classification including all the genera 
up to this time (it will be seen that they are few in number) ; it also, 
of course, shows Prof. Berlese’s views on the subject of the classifica- 
cation ; it will be most convenient to discuss the classification from 
this standpoint. The following is a translation of his table : — 
With exca- [ 
rations for I 
reception j 
of legs. I 
First pair of legs with ambulacra (claws and caruncle) . . 
„ „ without ambulacra 
Uropoda. 
Discopoma. 
fBody of adult and nymph protected by a fused dorsal and ventral) 7 
plate ... .. . / Dmyehus. 
Without 
such exca- 
vations. 
i 
Plates disappearing 
in adult, or body 
protected by nume- < 
rous plates, dorsal 
, and ventral . . 
\ 
Plates, especially the ventral, disappearing 
in the adult ; margins of all except the 
genital plate obsolete 
Dorsal and ven- 
tral plates con- 
spicuous 
r Genital plates 
well marked 
and distinct 
from the 
sternal 
'First legs! 
with am- > 
bulacra . . j 
First legs j 
without > 
ambulacra J 
Uroseius. 
Celssno. 
Polyaspis. 
Genital plate of the female j 
fused with the sternal 1 Uropodella. 
< plate ) 
It will be seen that Berlese’s first general division of the 
TJrojpodinde is that adopted by Kramer to distinguish his genus 
Trachynotus ; as stated above, I think that this method of differen- 
tiation should be utilized, and I have adopted it. Berlese, following 
Canestrini, next divides the creatures having excavations according to 
whether they have or have not ambulacra (i. e. claws and caruncles) 
to the first leg. I regret to say that I cannot agree that this is a 
