Of the Death-watch, 73 
The other death-watch is an infedfc different from the 
foregoing, that beats only about feven or eight ftrokes at 
a time, whereas the former will beat fome hours together 
without intermiffion, and its ftrokes flower, and like the 
beats of a watch. It is a fmail greyifh animal, much 
refembling a loufe; for which reafon it is called pedi- 
culus pulfatorius. It is very nimble, but extremely fhy 
when difturbed ; it will beat freely enough before you, 
and alfo anfwer you when you beat, if you can view it 
without giving it any difturbance, or fhaking the place 
whereon it lies. It is not certain whether they beat on 
any other thing but paper, their noife being heard only 
in or near it. 
Fig. 123. reprefents the fecond fort of death-watch 
as it appears to the naked eye. Fig. 124. fhews it a 
little magnified ; its fhape and colour is not much unlike 
a loufe; it is common in moft houfes in the warm 
months, but in the cold feafon of the year it hides itfelf 
in dry obfcure places, and is feldom feen; fome time 
after copulation, they lay their eggs in dry dufty places ; 
they are much more minute than the nits of lice, of a 
whitifh colour, and are hatched by the warmth of the 
approaching fpring, which to them is all the fame as an 
incubation : the infedt is fully hatched, and can creep 
about at the beginning of March, or fooner if the weather 
be warm ; at their firft quitting the egg-fhell, they are 
fo exceeding fmail, as fcarce to be difcerned, without the 
affiftance of a convex glafs : in this ftate Mr. Derham 
could find no other difference between them and mites in 
cheefe, when viewed with a microfcope that magnified 
much, but that mites had more briftles about the breech; 
in this fhape they continue fix weeks or two months, 
feeding on divers things they can meet with, after which 
they 
y Phil. Tranf. No. 291, 
r 
