Behavimr of Coleo'jptera in time of Floods. 388 
domen was cut off this moved very rapidly, as was also the 
case with S. hrunnipes. I did not induce any of the follow¬ 
ing to skim : S. dedaratus, S. lustrator, S. hiiphthalinus, 
S. himacidatus, S. providus and S. opticus. I was unable to 
experiment with enough specimens of some of these species 
(only one in the case of S. ojdicus) to definitely conclude 
that they cannot skim, except in the case of S. biqjhthahnus. 
On many occasions I tested this species under the most 
natural conditions and in bright sunshine with negative 
results. Among other genera I found one species which 
possesses this special power of locomotion, viz. Anch- 
omenus alhipes. When thrown on the water this species 
swims very strongly with the fore and middle legs, using 
the back ones very slightly or not at all. By this method 
it progresses at a good speed, but if carefully watched it will 
be occasionally seen to give a distinct but short spurt 
forwards, which however is sometimes rather more pro¬ 
longed. The legs are kept moving all the time, but the 
spurt forward is undoubtedly due to skimming, and when 
the apex of the abdomen is cut off it is found to skim 
for a short time. The beetle does not seem able to skim 
for long at a time, and those kept in a bottle for a short 
time refused to do so at all. There are many other closely 
allied forms and waterside species which might prove to 
possess the power of skimming if they were tested. 
A great number of beetles gain land when flooded out 
by swimming, and some land beetles are very strong 
swimmers. Here again there is much to be learnt as 
to the exact method of swimming each species adopts. 
The members of the genus Bemhidium upon which I have 
experimented {B. assimile, B. articulatum, B. nitidulum) 
swim very well. When B. assimile was flooded out by 
gradually immersing a piece of turf it took to the 
water quite naturally, and swam at a wonderful speed, 
moving the legs very rapidly as in running, the front legs 
which do nearly all the work being well spread out, the 
back legs being sometimes held still and crossed behind. 
Badister bipushdatus also swims well, using all its legs, 
the back ones often very strongly. 
Most of the Steni are good swimmers, even those that 
also skim; D. coerulescens, S. guttula and S. bipunctatus 
progress almost entirely by skimming, however. S. bimacu- 
latus moves quite rapidly by swimming and uses its front 
legs well spread out in a horizontal plane, as in Bembidium. 
