SCALY WINGED COPEOGNATHA. 4] 
minimal labels [Minutienklebzettel], according to the system of 
Ortner, Vienna. Morphological details can be studied in examples 
which have been softened in caustic potash, so that, on the whole, 
alcoholic material can be dispensed with. Before softening a unique 
specimen a precise description of it must be provided. Above all, 
the wings should be carefully removed before the softening process ; 
one pair should be preserved dry between two cover-glasses 
rimmed with wax; the other pair can, if necessary, serve for a 
Canada balsam preparation. 
As I have indicated on a former occasion* and then again, in 
greater detail, later, the method of softening is as follows :— 
The insect is transferred carefully into a mixture of one part of 
moderately strong caustic potash and about 8-10 parts of water ; 
(winged insects after removal of the wings) ; except when dealing with 
very delicate animals, in which case the s lution of caustic potash 
should be weaker. According to size and delicacy of the object 
it remains from ten minutes to several hours in the fluid, until it 
recovers approximately the natural form ; then it is transferred to 
water, where it must be watched since it now begins to swell. The 
larger air-bubbles are next carefully removed with a fine brush, and 
eventually the object is again placed in the dilute caustic potash. 
Here it can remain, at convenience, a longer or a shorter time ; 
even delicate examples can be left in the fluid for several days if 
the caustic potash is not too strong. 
If the object presents black and dark-coloured chitin, it is often 
necessary to leave it in the solution for a long time in order to dissi- 
pate the pigment completely. 
Finally, after the object has been washed out with water, it is 
transferred gradually into alcohol, where the smaller air bubbles 
can be easily removed. The animal can now be preserved in 96 
per cent. alcohol, and it retains perfectly the natural form which 
it had regained in the caustic potash. If a permanent microscopic 
preparation is desired, the contents of the body should be removed 
as far as possible by pressure with a fine brush, and the object having 
been properly orientated, is treated first with absolute alcohol, then 
with cedar oil, and finally mounted in Canada balsam. Cedar oil is to 
be preferred to clove oil, xylol, or benzol because the diffusion of fluids 
takes place much slower and consequently shrinkages rarely occur. 
*Giinther Enderlein. Eine Methode, kleine getrocknete Insecten fiir 
mikroskopische Untersuchung vorzubereiten in Zool. Anz. Bd. 27, 1904, 
pp. 479-480. 
+ Enderlein, Monographie der Coniopterygiden, Zool. Jahrb. Syst. Bd. 23, 
1906 (pp. 173-242), see pp. 174-176. 
