1 88 Correspondence. [ April 



tigate and describe some of these parasites of our birds. Most naturalists 

 nowadays own a camera and outfit, and also a microscope and its outfit. 

 This is my case. In the first place then I took my largest camera and 

 placed it on a long table as shown in the sketch. I removed its lens and 

 lens-board, and fitted a cardboard front to take its place at K. Next I took 

 mv largest microscope, — a Beck's Monocular National — and brought it 

 into the horizontal position. I fitted the upper end of its body, while in 

 this position, into the cardboard front of the camera (K). A substage 

 condenser, and a % inch objective were next attached to the microscope, 

 and the camera and the latter coupled together. Now most micro-pho- 

 tographers omit using the eye-piece of the microscope, but with it I sub- 

 sequently obtained the best results. It is inserted after the barrel or body 

 of the microscope is run through the cardboard into the front part of the 

 camera-box. 



For an illuminator! used the dark-lantern of my photographic outfit, — 

 simply withdrawing the ruby-glass slide in front, and fitting in its place a 

 thick piece of cardboard, into the centre of which I inserted the lens from 

 a small camera to act as. a 'bull's-eye condenser.' This is coupled with 

 the substage condenser on the microscope by means of a broad rubber 

 band, shown at r. My lantern I held nicely in the proper position by 

 suspending it between the 'rings' of a chemical standard, as shown in 

 my sketch; but any simple device will hold your lantern up in its proper 

 place. It can even be 'built up' by putting books under it. Both the 

 lantern and microscope rest upon a very thin board which travels with 

 ease on the extension-bed of the camera-box. By this latter simple con- 

 trivance, focussing your specimen on the ground-glass of the camera is 

 easily managed. The screws at f c, and /' control the whole thing, and 

 the rest can be with ease understood from my sketch of the plan adopted. 

 Yesterday afternoon (Feb. 27, 1894) I shot a specimen of Junco hyema- 

 lis, and immediately after getting it, searched through its feathers for 

 parasites but could find none after fifteen minutes' hard-looking. In the 

 throat-feathers, however, I found some minute, ellipsoidal egg-sacs, — 

 four or five in one place, and two in another. They were about one-tenth 

 of a millimetre long, and were attached to the calami of the semi-plumula- 

 ceous feathers so characteristic of most of the plumage of Junco. In 

 most cases there was but one sac attached to a feather, at the side of its 

 short calamus, but in two cases there were two sacs, placed exactly side by 

 side. They were in an advanced stage of development and their structure 

 could be easily studied with a high-power (one-fifth inch objective), 

 without staining. 



In a few hours my Junco was cold and rigid, and two parasites were 

 found upon his chin-feathers. They measured but a small fraction of a 

 millimetre, and were of the same species, — apparently $ and ?. One 

 was rather larger than the other and darker. I got them both on a 

 minute feather, and between two microscopic 'glass-slides,' and on to the 

 stage of the microscope. As soon as the light was turned on they were 



