"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. [Illustration: 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?"