"Can you tell us any thing more about this fly?"
"Nothing very strange, boys; but we have found out two tools, I think, a saw and a rasp, and that is enough for one poor little fly to give us. Here, boys, are pictures of these saws; I have made them a great deal larger than they are in the fly, so that you can see them plainly."
Saw of the Saw-fly, with Rasps shown in the Cross-lines.
Portion of the Saw-fly's comb-toothed Rasp, and Saw.
CONVERSATION II.
Uncle Philip tells the Children about Grasshoppers and Bees, that bore Holes with a Gimlet.
"Well, Uncle Philip, here we are again, to hear more about the tools that animals work with; we have seen in the bark of trees, and old wooden posts, little holes as round as a gimlet could make, and we have been thinking whether any of these little creatures have augers and gimlets, as well as saws. Do you know of any of them that can bore holes?"
"Oh yes, boys; I know of more than one that can bore as smooth and round a hole as any carpenter you ever saw. There are some of the grasshoppers that have an excellent gimlet. The contrivance has five pieces in it; two of the pieces make a case to keep the augers in, two more are the augers or borers, and the other is a piece between the two borers on which they slide; this piece has a ridge on each side of it, and the augers have a groove which exactly fits the ridge. Besides this, each auger ends in a knob, and that knob has teeth all around it. Here is a picture of it."
Ovipositors, with files, of the Grasshopper, magnified.
"But, Uncle Philip, what is the piece with the ridge for?"
"Ah, boys, that piece shows the wisdom and the goodness of God. 'His tender mercies are over all his works:' he has placed that piece there to keep the borers stiff, so that they cannot get out of joint, or be broken, when the little workman is boring."
"Well, this is very curious."
"Yes; but there are some of these insect workmen more curious still. Did you ever see a spy-glass? You know it is a round, hollow piece of wood, with brass tubes in it, which are made smaller and smaller, so as to slide into one another, when the glass is not used. Now there is a sort of gadfly (she is a little creature, too) which has exactly such a contrivance to keep her gimlet in. It is in four pieces, and the smallest piece ends in five sharp points, three of which are longer than the other two: she twists these five sharp points into one piece, and as some are longer and some shorter, when they are all put together, they make a sharp edge running all around, and are almost exactly like an auger or gimlet. When she wants to use it, she just shoots out the different tubes, so as to make a stem for the gimlet; and when she is done, she puts all back into its case again.
"Here is a drawing of it, and I think that by looking at it you will understand what I have been telling you: I do not know whether men learned from this part of the fly how to make the case of a spy-glass; but I know they might have learned.
Ovipositor or Gimlet of the Gadfly, greatly magnified, with a claw and part of the tube, distinct.
"There is also a bee, boys, which is called the carpenter-bee, because it is such an excellent wood-borer. It commonly looks for some old post, or dry plank, or withered part of a tree, to work in. It never works in wood that is green and has the sap or juices in it; for the bee knows, just as well as any carpenter does, that it is very hard to get tools through such wood. I expect that you have seen sometimes, when an old post or dry board was split, a long hollow groove in the middle of it, with little round thin pieces of something like paper, about as thick as a wafer, fastened in it by their edges, one above the other, all the way through. These show the work of the carpenter-bee: she bored the hole, and she put those little partitions like paper in it, to separate the cells; and more than that, she made the partitions out of the dust she got by boring. She always likes, too, to get a piece of wood in a place where the sun can shine on it; and when she has made her choice, she begins to bore at first into the post in a slanting direction, and as soon as she has gone far enough in, she then turns and bores straight, with the grain of the wood."
"Does she do it quickly, Uncle Philip?"
"Not very quickly, for sometimes the wood is very hard; I have seen one of these holes nearly twelve inches long in a very hard oak board. Sometimes she has to work at it for months; but she works steadily, boys, and that does a great deal. What makes it more tiresome is, that the poor little creature has to bring out all the dust she makes by boring."
"How large is the hole?"
"Oh, large enough to put my forefinger in, and sometimes fifteen inches long. After she has bored it as deep as is necessary, she begins to divide it into separate cells. So she commences at the bottom, and puts in a quantity of what is called bee-bread, until it reaches about an inch in height; on the top of this she lays an egg, and the bread is put there to feed the young one as soon as it comes out of the egg. She then makes a floor over it out of the dust, as I told you; she knows how to glue this dust together, and she brings it grain by grain from the heap in which she put it when she first brought it out: and she always begins by gluing the dust around the outside of the hole she has bored, and then glues another ring to that, and then another, and another, making each ring smaller and smaller, until she has it all filled; so that her floor, when it is done, appears like a parcel of rings of smaller and smaller sizes placed within each other. On the top of this floor she puts bee-bread, as before, and places another egg on it, and then covers it with a floor again; and so she goes on making cells and filling them with bread, and covering each with a floor, until she has filled up the hole."
"Uncle Philip, how do the young bees get out when the egg is hatched? It seems as if they were shut up for ever in prison."
"No, boys; there is a way for them to get out, and it shows the wonderful wisdom of God in teaching this poor bee how to contrive the matter. The egg which is put in the lowest cell being the oldest, the little worm that is afterward to be a bee will come out of that one first: now, you know, he never could get through all the cells over his head, filled as they are with bee-bread, so as to come out at the top of the hole. If he gets out at all, then, it must be at the bottom. The old bee knows this, and she so arranges these eggs that when the worm comes out it will be with his head pointed downwards; he falls to eating his bread, and so eats himself down to the bottom of his cell, and there he finds that his mother has bored a hole from his cell to the outside, and through that he comes out. When his brother in the cell above him has eaten his way down to the bottom of his cell, he just eats through the floor and gets into the cell below, which is then empty, you know, and walks out at the same hole which his older brother used before him. And so all the rest one after another eat their way downwards into the empty cells below them, and get out at the same back-door, which their mother made by what we call her instinct, which just means the share of wisdom which God gives to the lower animals to show them how to take care of themselves."
A, represents a part of a post, tunnelled in several places by the violet carpenter-bee; the stick is split, and shows the nests and passages by which they are approached.