1929] 
Identity of Xenillus clypeator 
125 
XENILLUS CLYPEATOR ROBINEAU-DESVOIDY 
AND ITS IDENTITY 
By Arthur Paul Jacot 
Shantung Christian University, Tsinan, China. 
In 1839 Andre Jean Baptiste Robineau-Desvoidy des- 
cribed a new genus and species of beetle under the above 
name, which he secured on the twelfth of J uly on agarics of 
an old cherry tree at Saint-Sauveur, Yonne (about 100 
miles south of Paris), France. General Dejean, to whom 
the unique specimen was presented, considered it an acarid 
and Lucas and Demary were appointed to restudy and re- 
port on it. They considered it as related to the Oribatids or 
Uropodids. It was then submitted through Mr. Audouin to 
Antoine Louis Duges who had made a few studies on Aca- 
rians, and who, referred it to Oribates castanse Hermann 1804 
(type locality Strasbourg) . Little did Duges realize, nor did 
anyone of that time, the fact that any mesophytic locality 
can boast of 60-80 species. A comparison of Hermann’s des- 
cription of O. castanse with that of X. clypeator brings out 
this point, the former being nearly spherical not ovoid, 
shining not granular, cephaloprothorax short, not rather 
long. 
A carefull perusal of Robineau-Desvoidy’s description 
reveals two important points (1) he mistakes the anterior 
pair of legs for antennae (giving them 5 joints) thus giving 
his animal three pairs of legs, instead of four, (2) he mis- 
takes the pseudostigmata for eyes. 
The description of Lucas and Demary who were, espe- 
cially Lucas, much more competant students, is far more 
detailed than that of the finder and is the basis for the 
present study. They describe the “antennae” as broken off 
so short as to leave but a small, cylindric pedicel. Their 
description includes three outstanding clues to the generic 
relations of this animal: (1) no plate or wing-like out- 
growths to the “carapace” (notogaster) are mentioned in 
