NOTES ON THE WHIRLIGIG BEETLE. 65 
brief duration, reminding one of similar actions on the part of 
the house-fly. Gyrinus always descends to the depths in a 
spiral curve. They frequently lie motionless on the surface 
from three to five minutes at a time. The heat of the sun 
always tends to make them more lively, but sunlight is not 
essential to them as to some insects, being frequently seen 
gyrating on cloudy and even cold days, but then only singly or 
in pairs. They are never seen in any large numbers until early 
summer is well advanced. 
For some reason which it is difficult to explain, in 1909 
the Whirligig Beetle was missing in some of its accustomed 
haunts, where previous to this I had never failed to find it. 
Though of small size—quarter of an inch in length—its surface- 
clinging propensity renders it easier of observation than those 
insects which habitually live beneath the water; for these can 
never be studied with any degree of confidence except in confine- 
ment, which even under the most favourable conditions cannot 
compare with that of their wild lives. Gyrinus does not take 
well to confinement, all attempts to keep these interesting little 
beetles in captivity always ending in failure. When thus kept 
they either ‘‘ sulk,’”’ lying motionless on the top of the water, or 
swim round and round beneath. Also they will not execute 
their characteristic whirl to charm their captor, but make all 
possible speed to quit their prison by climbing up the sides of 
the vessel they are placed in. This, disappointing as it is, 
is what would be naturally expected when we learn more of 
their mode of life. Let anyone who would wish to make them 
prisoners go for half an hour or so and watch them in their 
natural haunts, and he will soon become convinced of the 
futility of such an attempt. One might as well confine a 
Swallow in a large cage, and expect it to show there its powers 
of flight. Watch the widening and ever-widening circles, curves, 
turns, and twists of a number of Whirligigs; then it will be 
understood that room, and plenty of it, is what these insects 
desire. By rough calculation, I have determined that Gyrinus 
Measures while swimming, in less than the space of one minute, 
seven hundred and twenty times its own length; so that some 
small idea can be formed of the enormous area it would cover in 
the space of afew hours. And this calculation could only be 
