There are among insects strange resemblances. Insects of one sub-order will show a marked likeness to those of another. This is known as mimicry, and sometimes is wonderfully striking between very distant groups. Darwin and Wallace suppose it is a developed peculiarity, not always possessed by the species, and comes through the laws of variation, and natural selection to serve the purpose of protection. Now, right here we have a fine illustration of this mimicry. Just the other day I received through Mr. A. I. Root, an insect which he and the person sending it to him supposed to be a bee, and desired to know whether it was a mal-formed honey-bee or some other species. Now, this insect, though looking in a general way much like a bee, had only two wings, had no jaws, while its antennæ were closer together in front and mere stubs. In fact, it was no bee at all, but belonged to the sub-order Diptera, or two-wing flies. I have received several similar insects, with like inquiries. Among Diptera there are several families, as the Œstridæ or bot-flies, the Syrphidæ--a very useful family, as the larvæ or maggots live on plant-lice--whose members are often seen sipping sweets from flowers, or trying to rob honey and other bees--the one referred to above belonged to this family--and the Bombyliidæ, which in color, form and hairy covering are strikingly like wild and domesticated bees. The maggots of these feed on the larvæ of various of our wild bees, and of course the mother fly must steal into the nests of the latter to lay her eggs. So in these cases, there is seeming evidence that the mimicry may serve to protect these fly-tramps, as they steal in to pilfer the coveted sweets or lay the fatal eggs. Possibly, too, they may have a protective scent, as I have seen them enter a hive in safety, though a bumble-bee essaying to do the same, found the way barricaded with myriad cimeters each with a poisoned tip.