418 Mr. H. St. J. Donisthorpe on the Life History, 
tails, and the ants left them alone. I have discovered 
that when seized Lomechusa gives off the same smell as 
the species of Myrmedonia, and having dissected both 
under the microscope I found they possessed similar 
glands, which lie in the posterior part of the abdomen 
underneath the genitalia and alimentary canal, and contain 
the product which causes this smell. 
The larva of Zomechusa is very like an ant-larva in 
appearance, and although it possesses six legs it does not 
use them, but mimics the attitudes of an ant-larva. The 
Ji. 
Fia. 5. Larva of Lomechusa. 
ants value it very much, and on any danger threaten- 
ing the nest they carry it first into safety. That the ants 
feed it has been proved by giving them coloured sugar, 
when the colour can be traced in the digestive canal of the 
beetle-larva through the delicate white skin. They also 
place it on their own larvae, of which it devours large 
numbers, and Wasmann has shown that its voracity causes 
the production of ‘ Pseudogynes,’ or false females, in 
the nest. These are neither perfect females nor perfect 
workers, but of an intermediate form which does not work 
or bite. They are brought about in the following way : 
The numbers of worker-larvee consumed by Lomechusa 
causes a decrease in the workers produced in the nest. 
Now, as is well known, ants can create females by feeding 
their larve on special food, and to make up for the loss of 
workers they try to turn larvee which they have started 
to bring up as females into workers, the result being 
these “ Pseudogynes.” 
“ Pseudogynes ” only occur in nests where Lomechusa has 
been for some years, and they will not be found in all 
nests where Lomechusa is present, though of course the 
beetle will be found where “ Pseudogynes ” occur, and these 
nests are the centres from which the beetle spreads to 
other nests. 
At first the beetle is kept in check by the ants digging 
up its pupa and carrying it about as they do their own, 
which of course kills a delicate beetle pupa, but as more 
