1870. 135 
difficult to see how it could be placed there in any other way, though, 
as it in reality completes the cocoon of the larva within, it is hard to 
believe that its presence is accidental. 
I had usually found the pupation cavities placed vertically, 7. e. one 
set above the burrow, the inhabitants of which must be head downwards, 
the other set below the burrow, the inhabitants of which must have the 
head upwards; and it occurred to me, in connection with certain 
theories as to the sexes of bees, to investigate whether the different posi- 
tion had any influence on the sex of their inhabitants. Accordingly, I 
provided myself for the purpose with a fine log occupied by Platypus, 
but found, somewhat to my disappcintment, all the pupation cavities 
horizontal, that being the direction of the fibres of the wood in the log. 
The beetles were, I need hardly say, placed indifferently as regards the 
sexes. I tried to investigate the matter in a suitable stump, but was 
not successful in finding many beetles ready to emerge ; the few I found, 
however, did not favour any theory in the matter, but I was enabled to 
determine that the line of the fibres of the wood and not the line of 
gravity determined the direction of the pupation cavities. This must 
be of use in preventing the cavities of contiguous burrows from 
interfering with each other. 
When the beetle emerges, it soon leaves the burrow, and either 
forms a fresh burrow in the stump, or takes wing to a fresh locality. 
Those I had in captivity appeared to prefer the sunshine for their 
flight. It is only by taking them before they have left the burrows in 
which they were reared that they are to be captured in perfect 
condition. 
The beetles are able to make a very audible squeak, by rubbing the 
abdomen rapidly against the elytra. When a log containing a number 
of burrows is shaken, the beetles burrowing within it answer with 
- quite a chorus of squeaking, in order to hear which, the ear must be 
~ 
placed near the wood. 
I have never met with Colydiwm elongatum, the parasite of Platypus. 
The only parasite I have seen is a small white Acarus, a full-grown 
individual of which, until its legs are detected, extremely resembles in 
size, colour, and outline, the egg of Platypus, on which its eggs are 
laid, three or four sometimes adhering to the egg of the beetle. I 
believe it extracts nutriment from the larva of the beetle, though 
without doing it much injury. 
Abergavenny, August, 1870. 
