70 THE ZOOLOGIST. 
most of its foes. The milky, evil-smelling fluid that exudes from 
all its joints would, I imagine, render it an exceedingly nasty 
morsel to any other animal that would prey on it. Its convex — 
shape makes it difficult to hold, and in attempting to do this 
many a Whirligig has slipped through my fingers. The only 
pond-insects that would be likely to prey on it are Dytiscus, 
Notonecta, Naucoris, and possibly Nepa. The jaws of Dytiscus 
and the grasping legs of Naucoris and Nepa would experience 
some difficulty in holding such a slippery little object. Fish 
would no doubt swallow it with impunity, but Gyrinus generally 
inhabits waters from which fish of any size are absent. The 
pugnacious Stickleback doubtless attacks it, but the small mouth 
of this fish would not admit an insect the size of Gyrinus. More- 
over, its keen sense of vision, added to its celerity of movement, 
aids it considerably from most attacks. Kingfishers I suspect of 
occasionally preying on it, as I once watched one plunge several 
times into a small pond devoid of all fish-life, only being in- 
habited by Whirligigs and a few Newts. I wondered at the time 
what it was feeding on, and came to the conclusion it must have 
been these beetles, but, being afraid of driving away the shy 
bird, could not verify my suspicions. 
The early life of Gyrinus appears to be shrouded in a certain 
amount of mystery. Schiddte, in 1862, seems to have been the 
first naturalist to figure and describe the larva. Scherren says 
regarding it :—‘‘ The larva is not well known, and not often met 
with by collectors. Ihave taken examples in the River Ant, not 
far from North Walsham. When collecting there I was fortu- 
nate enough to find a couple, but one was damaged in putting 
it into a bottle. Both were found in pipe-weed (Entermorpha 
intestinalis), and it may be that this is the usual habitat. If so, 
it would quite account for the larva not being more frequently 
met with.’* I have never been fortunate so far as to find 
a specimen, but a very good figure and description of it will be 
found in Miall’s ‘ Aquatic Insects,’ referred to more than once 
in these pages. I can find nothing of importance on record 
regarding the breeding of Gyrinus, this doubtless being due to 
difficulty experienced in keeping the beetles in confinement ; 
but it is certain, from the observations of trustworthy observers, 
* ©A Popular Natural History of the Lower Animals,’ 
