1897J MICROSCOPICAL JOURNAL 



After a stay of several days in the alcohol the thread 

 was taken off and the fly washed in fresh alcohol, from 

 which it was transferred to a slender dish containing 18 

 parts of 95 p.c. alcohol and 2 parts of peroxide of hydro- 

 gen, from a freshly opened bottle of Marchand's solution. 



At the end of 24 hours, immersion in the solution the 

 abdomen of the insect had whitened somewhat; after 

 another 24 hours the thorax and the head had bleached 

 perceptibly and the eyes were seen to be losing their red 

 pigment. The specimen was now left for 48 hours 

 longer, and at the end of this time, 90 hours from its 

 first immersion in the peroxide solution, the whole insect 

 was as white as chalk. 



The specimen was then rapidly washed in stroii-^- 

 alcohol and placed for complete dehydration and stain- 

 ing at the same time, in 95 p.c. alcohol to which had been 

 added 1-20 p.c. of eosin, this staining agent being the one 

 recommended by most authorities for staining throujih 

 chitin on account of its great power of penetration. 

 After remaining for 24 hours in the alcohol-eosin bath it 

 was rinsed in fresh alcohol and placed in xylol to clear. 

 In an hour's time the whole structure had cleared per- 

 fectly and the specimen was mounted in xylol-balsnm in 

 a zylonite cell, and presented a most beautiful and in- 

 teresting appearance under the microscope. 



The chitin had been rendered almost as transparent as 

 glass, the eosin had given it a faint rosy tint while the 

 spine like hairs were more darkly stained; through the 

 transparent but very evident exoskeleton were to be 

 seen the muscles and their attachments and much of the 

 viscera; the abdomen was seen to be filled with eggs, ar- 

 ranged in two rows along each side of the median line 

 of the dorsum, the embroyos within the eggs were clearly 

 visible, the chitinous egg-shells having been rendered 

 very transparent, permitting much of the detail of th*^ 

 protoplasmic structures within to be seen. 



