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Springtails and Fishmoths — Part 3

Of all larvae none are more difficult to rear than those of the the saw-flies. Their mouth-parts seem to dry unless constantly lubricated by the saliva produced by mastication and once dried the larva usually dies. Fresh food must constantly be supplied and if possible they must not be allowed to descend to the surface of the sand; the latter must be carefully covered with paper, for if they once close their prolegs on a grain of sand they hold it convulsively and it is almost impossible to dislodge it so that they are practically unfitted for again clasping a twig.

The study of scale insects is a simple one. The food plants should be grown in pots and the insects colonized upon it. Most of the species remain stationary or nearly so and their location recorded, the exact situation of each individual under observation being circumscribed by a ring of ink marked with a pen upon the leaf.

The Aquarium.--Almost any of the different styles of aquaria which may be purchased will answer a good purpose. A very good one is shown in the accompanying illustration. Where it is desired to go rather thoroughly into the rearing of aquatic insects and where one is able to spend some money in preparations, the apparatus in use in my office is rather better than anything which I have seen. Two glass aquaria each 2 1/2 X 1 1/2 X 1 1/2 are placed end to end, the one elevated on a three inch base so as to make it that much higher than the other. The water connections from the one to the other are so arranged that each may be independent of the other, and the details are simply arranged. In each is a V-shaped inclined glass septum with a broad, deflexed lip, and beneath this lip has been constructed an artificial rock-work grotto. The water enters the first aquarium through a T sprinkler with six pipette orifices. It drops a distance of six or eight inches into the V-shaped septum and its force is easily graduated by stop cocks. Rising to the height of the deflexed lip it pours in a broad cascade into the main compartment, impinging on the top of the rock-work grotto. The second or lower aquarium is at present similarly arranged, and derives its supply of water either from the overflow of the first or independently from an overhead pipe, so that its water may be kept either still or running at will. Thus we have arrangements in a small space for the rearing of all kinds of aquatic insects. The sliding stream upon the artificial rockwork is particularly adapted for such forms as Simulium, and opportunity is also offered for such species as have the habit of crawling out either on rocks or earth, as the case may be.