COLLECTING AND PRESERVING INSECTS — BANKS. 71 



PREPARING WINGS FOR STUDY. 



It is very necessary in studying the venation of Lepidoptera to 

 denude the wings or to bleach the scales. Removing the scales with 

 a camel's-hair brush is the quickest method, but one is apt to injure 

 the membrane. Most entomologists use some sort of bleaching 

 process. Several of these are described below. 



Doctor Dimmock used chlorine in the form of chloride of lime. 

 The wings are first soaked in pure alcohol. The chloride of lime is 

 dissolved in 10 parts of water and filtered. A little is poured into a 

 shallow vessel. The wings are then transferred to this, and in an 

 hour or two are thoroughly bleached. When sufficiently clear the 

 wings are dipped into dilute hydrochloric acid, and then washed in 

 pure water and mounted upon a slide in Canada balsam. Doctor 

 Howard recommended the following process: The wing is removed 

 and mounted upon a slide in plenty of Canada balsam. The slide is 

 then heated over the flame of an alcohol lamp until the balsam 

 spreads well over the wing. Just as it is about to enter the veins 

 the slide is placed on ice, or, in winter time, outside of the window, 

 for a few minutes. This hardens the balsam immediately and pre- 

 vents it from entering the veins, which remain filled with air. With 

 practice one can select just the proper time when to remove the slide 

 from the flame and secure the best results. Doctor Smith recom- 

 mends the following method: He puts the wings in a mixture of 

 chlorine and hydrochloric acid. This decolorizes the wings at once, 

 and they may be mounted within a few minutes. The advantage 

 is in the rapid work. The disadvantage is in the vile odor of the 

 chlorine gas which is liberated by the mixing of the two liquids. 

 Doctor Calvert places the wings in a caustic potash solution for 

 twenty-four hours; then washes in water fifteen minutes; then in a 

 watery solution of Bordeaux red for twenty-four hours ; then washes 

 in water and floats on cards to dry. 



Mr. Tower recommends bleaching wings as follows: Place the wing 

 in a crucible partly filled with hydrogen peroxide and cover it. Boil 

 until the scales are bleached. Wash in water for fifteen minutes; 

 then in 70 per cent alcohol for a like time. Stain from one to three 

 hours with cyanin, gentian violet, or rosaniline. Remove from stain 

 and wash for fifteen minutes in 50 per cent alcohol, and for thirty 

 minutes in water. It may be necessary to repeat this washing if the 

 stain is not removed from the membrane. Then mount in glycerine 

 jelly. For balsam mounts, bleach as above; then wash in water, 

 and in 50 per cent alcohol each for fifteen minutes; then remove and 

 stain in cyanin for two hours; then wash in 50 per cent, 70 per cent, 

 and 90 per cent alcohol, ten minutes in each. Remove the surplus 

 stain and air bubbles by thoroughly washing; clear in oil of cloves; 



