The Bionomics of the Tiger-beetle. 7 
were therefore isolated, and each was placed along with one male, in a small 
breeding-cage thickly sanded at the bottom. Here the egg-laying habits 
could be watched conveniently. Eggs were never laid on cold, dull days, 
but in sunny weather the female beetles would extend their ovi-positors, 
feel the ground for a suitable spot, and commence to bore, breaking up the 
earth with two pairs of curved horny points, with which the tip of the 
ovi-positor is provided. One or two pits so commenced were usually for 
some reason abandoned, before an entirely satisfactory spot was found. Such 
pits persist and are visible for weeks in fairly firm soil or turf. When 
the egg has been deposited the beetle carefully fills up the hole again, and 
lastly rakes over the surface with her curved picks. The whole process of 
Ovi-position occupies from 15 to 25 minutes. On one occasion during a 
period of constant watching a beetle was seen to ovi-posit five times between 
9 AM. and 2 P.M.on a sunny June day. Later in the day the weather 
became cloudy and no more eggs were laid. But repeated observation went 
to show that the activity of this beetle was by no means exceptional. Indeed 
it would seem that under the stimulus of sunshine a beetle feels impelled 
to get rid of her eggs, though the rate of ovi-position is restrained by the 
careful and deliberate manner in which it has to be performed. If a beetle 
is so disturbed in the act of ovi-position that she withdraws her ovi-positor 
at the critical moment from the pit she has made, and the egg gets laid on 
the surface of the soil, she will turn round excitedly and devour her egg. 
Several of the harassed beetles mentioned above carelessly dropped their 
eggs anywhere ; the other beetles showed no disposition to eat the dropped 
eges of their companions, and if such an egg was not devoured by the 
female herelf, as it sometimes was, 1t would remain untouched. 
In July (1915) observations were made in the open in Argyllshire 
which confirmed in all particulars those already made on the egg-laying habits 
of these beetles. In a little clearing among the heather ofa hillside a 
female was surprised egg-laying. She ran off into the heather, but, perfect 
stillness being observed, she came back and re-commenced operations. 
Extending her ovi-positor she felt about over the soil surface, and after 
rejecting one or two spots eventually excavated her pit, ovi-posited and 
covered up the place. The ground was dry, and breaking it up with the 
horny points at the end of the ovi-positor was unmistakably hard work. 
As the hole deepened the beetle raised herself on her front legs till her body 
assumed an almost perpendicular attitude, and not only the ovi-positor, but 
the posterior part of the abdomen itself became sunk in the earth. A pause 
in the exertions indicated the passage of the egg, and then the work of 
filling up began. This also was done slowly and carefully, and lastly the 
