GO 
THE WEEKLY ENTOMOLOGIST. 
this would be favourable for these 
insects supposing they really flew 
from the coasts of France. 
“16th. Oct. 1862. Passing through 
the Straits of Gibraltar to -day, several 
moths flew on board, among others I 
took a splendid specimen of Margar- 
odes Unionalis. Hub.” The weather 
was frightfully hot. I suppose these 
insects were taking a trip from Spain 
to Africa, and vice versa. — G. F. 
Mathew, Portsmouth, March 10 th. 
1863. 
Notes. I am disposed to think 
that the “ mity ” appearances of brown 
powder, often found under the bodies 
of Lepidoptera in Cabinets, and as- 
cribed to the ravages of mites, may, 
not unfrequently, be traced to a very 
different cause. Such is certainly, 
my own experience, which I will 
now briefly give you in a rough form. 
About twenty years ago I arranged 
my collection of British Butterflies 
and Moths in a cabinet of foi'ty draw- 
ers, — an excellent piece of workman- 
ship from the hands of old Standish. 
The drawers were carefully camphor- 
ed, and every insect cleaned and 
narrowly scrutinized, before it was 
placed in the drawer. I do not think 
that one specimen infested with acari 
could have escaped my eye. How- 
ever, after a few years, (al tough the 
drawers were almost airtight and kept 
well supplied with camphor), small 
collections of powder appeared here 
and there under certain insects. 
These were taken out and immersed 
in spirits of Turpentine to kill the 
supposed mites, and w 7 hen properly 
dried were replaced. Well, this 
went on for a good many years, dur- 
ing which I noticed that after a cer- 
tain time powder always made its 
appearance under the same specimens, 
and lately, having occasion to re- 
arrange the whole of my cabinet, I 
found, to my great dismay, that 
nearly a fourth of my collection of 
moths was, to all appearance, suffer- 
ing, or had suffered, from the attacks 
of Acar us Destructor ! Now I felt 
sure that such could not be the case, 
and that the powder lying under 
the bodies of the insects must have 
been produced by some other cause. 
I therefore subjected the underside of 
the bodies to a microscopical examin- 
ation, and soon found out what the 
cause was. The brown powder re- 
sulted from natural decay and disin- 
tegration. In every instance I found 
that where the body had been injured 
either in the capture of the insect, or 
in the setting out, or in travelling, 
or from any other accident, decay 
had commenced, and its results, in the 
shape of small dust-like particles, had 
found their way through the orifice 
caused by the injury. To make this 
fact more clear and certain, I ascer- 
tained, by examination, that not one 
specimen, the skin of whose body 
was sound and unbroken, showed 
any signs of dust or powder beneath 
it, whatever ; and, on the other hand 
that the more extensive the wound, 
the larger was the collection of the 
(at first supposed) mite dust. In 
the case of those insects which 
