10 Mr. MoxTaGv's Description of several new or rare Animals, 
the pectoral combs, and the articulated tail armed with a spine. 
De Geer has very properly instituted a new genus for it under 
the title of Chelifer, to which the cancroides and the other species 
figured by Kanmacher should be referred *. 
_ It will be observed that the P. acaroides differs from the last- 
mentioned species in being destitute of the cleft on the inside of 
the thick part of the claw, or rather the hand, which is so conspi- 
cuous in the species figured by Kanmacher, and which species 
at present seems to be the only one noticed in this country, 
although that author remarks that he received four from Holland 
very perfect. 
The absurd idea, tliat either this or the P. cancroides gets into 
persons' legs and creates humours, is certainly without founda- 
tion, neither of them being furnished with a proboscis like the 
Acarus; and it is more than probable the habits of Acarus au- 
tumnalis have been ascribed to these insects. That little crea- 
ture, almost invisible to the naked eye, abounds in dry summers 
so much as to be extremely distressing to those who enjoy rural 
sports; and where the habit is readily excited to inflammation, 
dreadfully inflamed legs will frequently be the consequence, 
of which I have known several instances. I have found this 
species of Acarus particularly attached to raspberry bushes, and 
in this situation it usually attacks the arms as well as the legs of 
those who are in the habit of picking the fruit. 
The P. cancroides is more commonly found amongst —— 
* Dr. Shaw thinks, from the ee truncated form of the abdomen of this insect, that 
it constitutes a distinct species from the P. acaroides, and might not improperly be named 
P. truncatum. The insects of this tribe may be allowed to form a separate genus, nearly 
allied to that of Scorpio, under the title of Cheli lifer, the name applied to them by De Geer. 
The P. cancroides is certainly furnished with a pair of pectinated organs resembling those 
of Scorpions, though in a somewhat different situation, being placed nearer to the head, 
of 
