Page:Hardwicke's Science-Gossip - Volume 1.pdf/263

Collectors thus employed, are generally objects of great interest on the part of bakers' and butchers' boys running their masters' errands, and of the public at large, if the weather permits them so to be. In the present instance, as I stood over a pond, occasionally making a dive with the water-net at something which rose for an instant to the surface, these parties stopped. One was heard to say in an undertone to another who had been looking on for some time, "What is that cove catching?" The reply was, "Don't know,—think it's tiddlers. O! there! he's got something; come and see." Then they came closer, looked into the bottles, and made sundry comments to one another on what they saw. Occasionally their comments were diverting, but more frequently otherwise.

Perplexed whether the box ears all round, or to wait till the rain should tire out their inquisitiveness, it was a relief to notice that two individuals equipped with rods and lines, evidently thinking this a good place for their sport, stopped short in their walk, and got out their tackle and commenced operations.

Now, it was more than probable that the only representatives of the finny race in that piece of water—seeing that it was only a horsepond—were sticklebacks, or, as the boys said, "tiddlers:" consequently, the prospect of "good sport" was not great. Nevertheless, the anglers perseveringly plied their vocation for a good hour, not even getting one of the above-named fishes during the time. Perhaps I should not tell this much of their exploits, because I felt under obligation to them, since their arrival had diverted attention away from my proceedings.

To be pestered by small boys, inquisitive old ladies, or practical jokers, is the inevitable fate of the collector. His bottles and apparatus invest his proceedings with mystery, or furnish materials for ridicule. It is not very gratifying, for instance, when you are busy in some field by a roadside, getting specimens out of a pond, to hear the alarm given, "Stop him: he's going to drown himself," and find that you are the individual referred to. "Vox populi, vox diaboli," you mentally ejaculate; but you settle down, and, like John Bunyan, grin and bear it.

Plenty of whirligig beetles (Cyrinus natator) were obtained from the surface of the river Ravensbourne, which runs through a field close by the Shortlands Station. A slide containing a good specimen of each of the three pairs of legs of this water beetle, common almost everywhere, is well worth the trouble of preparation. They must be mounted in balsam, and form a beautiful object for either transmitted or polarised light.

In a horsepond just out of the town of Bromley, on the left-hand side of the road going towards Keston, were caught nine Dytiscus larvæ—three full-grown, and six small. Experience having shown that these larvæ are anything but friendly-disposed towards each other, they were severally wrapped in grass, and taken home in this condition.

The ferocity of these tyrants of fish-ponds is quite equal to their powers. Once I kept one in a basin of water for a fortnight, during which time he ate seven or eight tadpoles, besides sundry earthworms, and grew so large that he cast his skin twice. If a small stick were presented to him, he would grasp the end boldly; that mode of testing his bravery being deemed more prudent than offering him a finger, which, judging by his manner of despatching tadpoles, might have been painfully made acquainted with the sharp points of his mandibles. One gripe was sufficient to settle any tadpole, and was always taken through the sides, apparently quite transfixing the poor little wretch, which quivered while life lasted, its enemy meanwhile keeping tight hold and sucking its juices, till nothing but the blanched skin was left to tell the tale.

Earthworms were more trouble to him, since, owing to their violent struggles, he was obliged to divide the larger ones and eat them piecemeal.

Perhaps the most interesting part in the structure of the larvæ Dytiscus is the tracheæ. Tracheal tubes of insects at all times are beautiful microscopic preparations, and those to be obtained from this ferocious creature are among the finest. A careful incision with the fine scissors down the centre of the back, and repeated washing, after a prolonged soaking in ascetic acid, enables one to remove them from the skin of the insect almost entire, provided the hand be light and a sufficient amount of patience be used.

The only implements employed by the writer are, the scissors to cut the skin open, the forceps to detach the tracheæ which lie along each side, and a camel's-hair brush for washing and occasionally assisting the forceps. Of course, the insect must be