Fig. 68. A water-tiger.
The water-scavenger beetle ([Fig. 69]), so called because of its appetite for decayed matter, is common in many ponds. It has, like the diving beetle, a hard, shiny back, with a straight line down the middle, but the two can be distinguished when seen together. The young of this beetle look and act something like the water-tigers, but have not such great ugly jaws.
Fig. 69. A water-scavenger beetle.
There are three other swimmers even more delightful to watch than those already mentioned. The water-boatmen ([Fig. 70]), with their sturdy oar-like legs and business-like way of using them, are droll little fellows. They are not so large as the back-swimmers. Fig. 71 shows a back-swimmer just in the act of pulling a stroke. These creatures swim with their boat-shaped backs down and their six legs up. We must be careful how we handle the back-swimmers, for each one of them carries a sharp bill and may give us a thrust with it which would be painful, perhaps poisonous.
Fig. 70. Water-boatman.
The water-scorpion ([Fig. 72]) is a queer creature living in a neighborly way with the boatmen and back-swimmers, though not so easy to find. Do not throw away any dirty little twig which you find in the net after a dip among water plants near the bottom of a stream or pond. It may begin to squirm and reveal the fact that it is no twig but a slender-legged insect with a spindle-shaped body. We may handle it without danger, as it is harmless. This is a water-scorpion, and his way of catching his prey and getting his air supply will be interesting to watch. He is not shy and will answer questions about himself promptly and cheerfully. [Fig. 72] will give an idea of the size and appearance of this insect.
Fig. 71. A back-swimmer.