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I . — On the Markings of the Body-scale of the English Gnat and 
the American Mosquito. 
By Dr. J. J. Woodward, U. S. Army. 
( Bead before the Royal Microscopical Society, May 3 , 1876 .) 
Plates OXXXIX. and OXL. 
My attention was first directed to the markings on the body-scales 
of the English gnat by a letter received last summer from Mr. John 
Mayall, jun., enclosing a mounted slide of these scales, and a photo- 
graph of a drawing of one of them by Dr. John Anthony, of Bir- 
mingham, representing the scale as marked by longitudinal beaded 
ribs, having three uniform parallel rows of smaller beads in every 
interspace betiveen two adjoining ribs. (See PI. CXXXIX.) 
Mi-. Mayall stated that Dr. Anthony had made the drawing to 
represent an appearance of the scale glimpsed by central light, but 
had not been able to show this appearance to him in the microscope 
as definitely as it appears in the drawing, and requested me to 
undertake to photograph the scale as seen under the microscope. 
This I did at such leisure hours as I was able to command during 
the latter part of last year, and in so doing arrived at results which 
may perhaps be of interest to some of your Fellows. 
I at once observed the very great similarity between the scales 
of the English gnat and those of the American mosquito, with 
which I had been familiar for a number of years ; a similarity 
which relates to all the details of surface markings, as well as 
to the size and general outlines of the scales. In the case of the 
mosquito, I had seen that the scales are crossed transversely by fine 
markings, probably ridge-like corrugations of the thin double mem- 
brane composing them, and that these transverse markings crossing 
the longitudinal ribs at regular intervals, gave to the latter a beaded 
appearance ; but I had not believed that the transverse markings 
were also beaded. I must add that the ribs and transverse mark- 
ings exist on both surfaces of the scale, though much more boldly 
on one than on the other, and that the longitudinal ribs of the 
opposite sides unite at the broad end of the scale, where they 
generally project as bristle-like appendages beyond the general 
contour. 
My examination of the slide received from Mr. Mayall has led 
