Excerpt from The Microscope, Vol. 3: An Illustrated Monthly Designed to Popularize the Subject of Microscopy
These two-winged insects belong to the class Diptera which is composed of twenty-eight families. The house-fly, the blow-fly, the horse-fly, the mosquito and others with which we are familar belong to this class.
The little house-fly (Fig. 1) is called Musca domestica. But it is now midwinter and where shall we find a fly? Go to some place where meat is sold or to some out of the way hiding place. A last summer's fly may still be clinging to a spider's web or to the wall. If not dead, kill it by putting it in a large-mouthed bottle containing a little chloroform.
Now open the Excelsior microscope described in the last number and arrange it as shown in the Dec. frontispiece, placing the flat side of the glass stage G up, and the smallest of the lenses F nearest the glass stage. Put. the instrument near a window with the mirror toward the light; turn the two largest lenses so they will come directly over the mirror and put the case containing the small lens and the diaphram at right angles to the lenses so that it will not interfere with the moving of the screw in the stage. Now slant the mirror so that on looking through the lenses you will have a white field. Place the fly on the centre of the glass stage, as though he were walking, and having loosened the screw in the stage, move the stage up and down very slowly until you can see the fly distinctly, and then fasten the screw. This is focusing the instrument. As the fly is quite thick and the light comes to a focus at one point only, you will not be able to see all parts with equal distinctness, but look at the head and hack first, then focus again for the legs. With a little patience and practice you will be able to get a good focus quickly.
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