24 
NATURE NOTES 
proved the most insidious and formidable foes to infant trout I 
ever had to fight. In many streams they escape notice, and are 
not so numerous in some as in others. They flourish to the 
greatest extent in those waters which, like my moats, do not 
freeze even in the severest weather, owing to their proximity to 
the spring. To give an idea of their numbers, I once placed a 
piece of fresh meat in a saucer in the lower moat, and on 
removing it two or three hours later secured 1,200 leeches. As 
sediment is fatal to trout ova I filtered the water for my breeding 
boxes by passing it through sand ; but in spite of all my care 
the leeches got into them on one occasion, and cleared off a 
thousand fry that were newly hatched. Half-a-dozen of these 
small leeches were placed as an experiment in a saucer with 
three or four fry fresh from the egg. These were attacked at 
once, nothing being left but empty skins. The leeches, however, 
could make no impression upon some ova in the saucer, owing 
to the toughness of the envelope. 
As soon as the umbilical sac was absorbed, I turned my 
troutlets into a very small artificial pond by themselves. Here 
numbers were attacked by a leech of another kind, which was of 
a light green colour with dark rings, and had a powerful sucker 
at one extremity. These leeches, which are commonly to be 
seen on the head and eyes of adult fish, are of the same size 
and not unlike the so-called “worm ” that causes the “gapes” 
in young pheasants by adhering to the larynx. These leeches 
fix upon the gills of the little fish, causing them to bleed. I have 
placed the fish, when thus attacked, in a bowl of water, and 
have removed the leech ; but in no case could I save their lives. 
There are many other enemies, almost as intangible and 
mischievous as leeches, which are to be met with in countless 
numbers in every piece of water the country through. 
“ Whirligig ” beetles, which amuse us by their antics in some 
quiet corner of stream or pond in early spring, are not only 
savage in their attacks on other creatures, but their larvae are 
also carnivorous. The same may be said of the “ Water-boat- 
man,” whose proboscis has inflicted a stab on many an unwary 
finger. “ Water scorpions,” both as larvae and as perfect 
insects, lie in ambush in the mud “seeking whom they may 
devour.” Indeed, as a class, aquatic Heteroptera, to which group 
water-boatmen and water scorpions belong, are enemies to any 
form of life they are strong enough to master. 
Water-beetles are numerous and ubiquitous. Their larvae, 
like the perfect insect, are in almost all cases carnivorous, feed- 
ing upon “ flesh, either living or dead,” and are provided with 
terrible weapons to secure their prey. Of them it is said that 
“ their jaws are formed after a curious fashion, being perforated 
throughout their length, as the poison-fangs of a serpent, so as 
to serve not only to capture and retain their prey, but also as a 
medium through which the juices can be sucked into the mouth. 
. . No sooner does an insect or other small creature appear 
