Beck,, on the Reproduction of an Acanis. 33 
in e?ery stage of development ; the empty egg shells from 
their extreme thinness reflecting a brilliant blue lights which 
catches the eye more quickly than the acarus itself. 
My object from the first in securing this acarus_, and in 
keeping it alive was to obtain specimens of both sexes^, but I 
have never yet been able to detect a male. I was much sur- 
prised to find that every specimen I selected laid eggSj all of 
which duly hatched, and to make sure whether this was really 
a case of agamic reproduction^ I determined to isolate some 
individuals very carefully,, and I obtained the following 
results. In all these experiments I have employed the *^^live 
traps which I described in the last number of the Micro- 
scopical Journal of Science^ and they have answered per- 
fectly, not only in completely isolating the specimens, but 
also enabling me to put them under the microscope, or to 
supply them with food at any time without disturbing them 
in the least. 
On July 10th, of this year, a young acarus of this species 
was taken from a trap in which there was only a mature 
female ; it was completely isolated, and on the 29th of the 
same month it laid eggs^ which hatched on the 4th of August, 
One of these on the day it was hatched was removed to a 
trap and also completely isolated ; by the 13th of September 
it had laid eggs, and some had hatched. On the 19th of 
September two of the young from the last mentioned trap 
were separated and secured j these I now have living and in a 
mature state, neither have as yet laid eggs, but I fully expect 
they will do so unless the approach of colder weather retard 
the process of reproduction, Y>^hich I think is very probable, 
or it may perhaps stop the increase altogether."^ 
The securing a succession of three generations, including 
some accidents, have with me extended over a period of about 
five months, and I am quite prepared to admit that the proof 
of agamic reproduction in this acarus would have been more 
satisfactory if continued through a longer period, but after 
reading Professor Huxley^s Paper on the Agamic Reproduc- 
tion of Aphis, in part of which he states that " in Myriapoda 
and Arachnida the process is not known/^t I have thought 
that the few facts I have just given were of sufficient value to 
bring before your notice. 
* (March 16, ] 866.) Since writing the above, one of the specimens 
last referred to was icilled; the other laid eggs which hatched on the 29th of 
December, and one of these young ones is still alive, but isolated in the 
same way as its predecessors. The cold of the winter has retarded the 
development of these acari very considerably, and so much so as to allow 
the other colonies of acari to appear again in their wonted numbers. 
t 'Linn. Trans./ vol. xxii, part 3, p. 216. 
