I often notice the great difference of character that exists in insects. These drone-flies do not appear to be at all unhappy in captivity, they become so tame as to come on my finger and accept any suitable food placed there, and after they have been flying about they will walk into their globe as if perfectly content to abide in it. Not so the honey-bee. A specimen was on the window-pane one very wet and stormy day, and fearing it would die if I let it out of doors I introduced it among the drone-flies. They, good, easy-going creatures, were quite friendly towards the stranger, but the poor bee could not settle down—it fussed all day up and down the glass, despised the sweet provender, and, fretting, I supposed, at its absence from the community, was found dead next morning.
One day in January I gathered a spray of sweet-scented coltsfoot in flower, and placing it in a glass of water, enjoyed its delicious perfume. Supposing it might contain some honey and prove acceptable to the drone-flies, I let them investigate the flower, with the result that they speedily became covered with its white pollen. I feared this might clog their yellow down, and was about to brush it off with a feather, when I saw, rather to my surprise, that the flies were greedily devouring the pollen grains, brushing them off their downy bodies by means of the combs on their fore-legs, and then the flaps at the end of the proboscis rapidly picked up each grain until there was not one left. I am glad to know this fact about their diet, as I can now give the interesting pets both liquid and solid food, which will no doubt help to maintain them in health and vigour.
We will now turn to the larvæ stage of these flies when, as purifiers of the foulest putridity, they are doing us most essential service. The fly lays its eggs in the mud of some stagnant ditch, and out of each of them emerges a whitish worm-like grub with a long tail, which is its breathing apparatus, and must therefore always reach to the surface of the water. It is formed of graduated tubes, which can be retracted or drawn out exactly like a telescope. If the water is shallow, only one or two tubes are needed, and the tail appears somewhat thick, but if, owing perhaps to a sudden shower, the water deepens, then the creature can draw out tube after tube until the tail is two inches in length, and graduates to a thread-like point. If these grubs were thrown into deep water they would be drowned, being suffocated from want of air, but in ditches, where they are usually found, they can crawl along in the mud by means of very small legs on the thorax and abdomen, and ascend the sloping bank until they reach the needful air. Respiration is carried on by means of a double air-tube within the tail. When at its full expansion these tubes lie parallel to each other, but when the tail is retracted the tubes fall into two coils at the base, where it issues from the body of the grub—truly a marvellous piece of mechanism for such a lowly creature. The most noisome black mud is the favourite habitat of this rat-tailed maggot, as it is called, and to it we owe a deep debt of gratitude, since, repulsive as it may appear to our eyes, its life-work is to purify such foul places as would pollute the air we breathe; it feeds and luxuriates upon that which is full of the germs of fever and mortality to us, and then, when full grown, it buries itself in the ground to come forth in due time as a bright-winged fly.
Even in its perfect state it is doing us service, for in seeking pollen for its food it helps to fertilise our fruit-tree blossoms, being seen upon them in the early days of March, long before other tribes of winged insects (excepting bees) are to be found abroad. The early spring sunshine attracts them from the nooks and corners where they have been hibernating through the winter, and greatly do they seem to enjoy rifling the newly-opened flowers of our apricot and peach-trees.
The specific name of Tenax given to this fly shows its power of clinging firmly to any object on which it settles. Each leg is furnished with a pair of strong curved claws which, when closed, appear to be like twelve grappling irons, and may well account for the tenacity of hold which the fly possesses.
From the interest I have found in keeping my drone-flies, I feel encouraged to try and learn more of the habits of other flies and insects. I believe in this way many curious facts may be ascertained about the life-history of many little-known species which are seen for only a limited period of the year, and whose further doings have not as yet been fully traced.
THE PRAYING MANTIS.
“O crooked soul, and serpentine in arts.”
Dryden.