464 
mttS; 
with the thighs of the two upper pair of legs ex-* 
tremely thick and short, but the tarsi or continua- 
tions very slender, apparently tubular, transparent, 
and terminating in a rounded tip: the two lower 
pair of legs have thick, oval-oblong thighs, pro- 
ceeding from a very slender base, and are extend- 
ed into an extremely long, stout, curved, and 
sharp-pointed bristle. The figure of this insect by 
Bononio, engraved in the Philosophical Trans- 
actions, cannot be commended either for elegance 
Or accuracy: that of Degeer is sufficiently correct; 
This I am enabled to state with confidence, having 
been favoured with several specimens of this ex- 
traordinary animal by Dr. Baker, whose ingenious 
observations on its nature and qualities were com- 
municated to the Royal Society in the course of 
the last winter. Dr. Baker, during his residence 
at the Madeiras, had ample opportunities of in- 
vestigating the disorder occasioned by it, and is 
inclined to think that it constitutes a species of 
Psora distinct from some others which are usually 
confounded with it, but which arise from some dif- 
ferent cause. 
Acarus autiimnalls, popularly known by the 
name of the Harvest-Bug, is also one of the most 
minute of the genus, and is of a bright red colour, 
with the abdomen beset on its hind part with 
numerous white bristles, lliis troublesome insect 
will make itself sufficiently known to most jieople 
during the montlis of July, August, and Septem- 
ber: it is easily distinguishalile on the skin by its 
bright red colour and adheres so tenaciously when 
