204 General Notes. [ February, 
view before stated in regard to the function of the com- 
ant purpose. This view rests on the fact that if the ocelli are 
covered with opaque black varnish, the insect guides its course in 
the same manner as before. 
While these experiments may be said to favor the conclusion 
arrived at by Plateau, they do not, in my opinion, furnish decisive 
evidence. It would be quite within the range of possibilities, that 
the insect distinguished perfectly well the forms of both the large 
and small holes, without taking in the relation of its own size to 
that of the hole through which it sought to escape. The power 
to distinguish forms is not tantamount to a knowledge of relations 
that could only be learned by experience and reflection. 
A METHOD oF BLEACHING WiNcs oF LEPIDOPTERA TO FACILI- 
TATE THE STUDY OF THEIR VENATION.—In the common method 
of destroying the scales on the wings of Lepidoptera, for the pur- 
pose of studying their venation, by means of caustic alkaline solu- 
tions, there is danger of not arresting the action at the proper 
moment, and consequently of destroying not only the portions 
which it is desirable to remove, but also the scale-supporting 
membrane, and even the delicate veins themselves. An applica- 
tion of a modification of the chlorine bleaching process, commonly 
used in cotton bleacheries, obviates the necessity of removing the 
scales, and Jeaves the wing perfect. 
alcohol in order to dissolve out the oily matter in them. If this 
is not done the surface of the wings acts as a repellent, and will 
not be moistened by an aqueous solution. When the wings have 
become thoroughly soaked by the alcohol they are ready to be 
removed to a solution of common bleaching powder. This bleach- 
ing powder is sold by druggists as “chloride of lime,” but it is 
` really a mixture of calcic hypochlorite, calcic chloride, and calcic 
hydrate. Ten parts of water dissolve the first two compounds, 
leaving nearly all the third suspended in the solution. The solu- 
tion should be made with cold water, filtered, and kept ina tightly 
corked bottle until required for use. When the wings are trans- 
to this solution the bleaching commences, and in an hour 
or two the wings are devoid of markings, although the veins re- 
tain a light brown color. This is due to the fact that chlorine 
cannot quite decolorize animal matter, or any substance contain- 
ing nitrogen, as it does vegetable tissue. 
After the color has sufficiently disappeared from the wings 
they should be transferred to a wash composed of one part of 
1G. Dimmock, Proceedings of the American Association for the Advancement 
of Science, Detroit meeting, August, 1875. 
