Page:Hardwicke's Science-Gossip - Volume 1.pdf/99

1, 1865.]

called house-fly is upon the average of six to one in my little compartment.

Mr. Samuelson and Dr. Hicks published in 1858 a small but interesting book in a series of eight letters upon the "Common House-Fly," and as number one and two of mine represent their in every particular, with the exception of number two bringing forth a live grub, I would wish to ask to what class we are to place number two and three—are they also to represent the common house-fly? If so, we have three distinct varieties, and in all probability many others.

It occurred to me, and also to several of your subscribers, that a paper upon this subject might not be altogether uninteresting or out of place in your instructive, as it may lead some one more able than myself to solve the problem.

In the same series of letters to which I have made reference, the facets in the eyes of various insects are enumerated; among the number mentioned is that of the dragon-fly (Libellula). I believe it is not generally known, or perhaps only known to myself, as I have never heard it mentioned, that the eye of the dragon-fly consists of three distinct separate layers, which may with careful manipulation be separated, showing the facets more distinctly. I have one so obtained mounted for the microscope. I acknowledge it will require a very steady hand, a little skill, and plenty of patience. It is more than ten years since I made this discovery, and perceiving that no naturalist mentions the circumstance, I thought it might be interesting to those who are fond of insect anatomy.

I will also mention another object which will richly repay the trouble of mounting: the gizzard of the flea, thoroughly cleansed and skinned, is a most splendid object for an objective (mounted in Canada balsam). 2em

[N.B.—Our correspondent's drawing was too rough for engraving, and we have substituted the tongue of the drone-fly, which he states his own much resembled, except that it was smaller, and more opaque in the trunk.—''Ed. Sc. G.'']