SOUTH AFRICAN CATERPILLARS 18T 



For the preparation of the very small larvae, siicli as 

 first instars, the small Tincidac, etc., it had been advised 

 to heat the entire larva in a test tube over a small flame. 

 At first the larva contracts and the stigmata are closed. 

 By continued heating the air contained in the larva 

 causes it to expand and stretch out again. But this 

 method has not proved very successful with us and we 

 have abandoned it in favour of inflating even the smaller 

 caterpillars in a manner similar to that described for 

 the larger ones. This takes a steady hand, great care 

 and much patience; but the results well repay the 

 trouble. The small larva can be killed in the usual way. 

 It is then boiled in weak potash solution. By continued 

 boiling we find that sufficient of the alkali penetrates to 

 soften the tissues inside and after a wiiile we find the 

 practically empty skin with the greater part of the 

 alimentary canal projecting from the back. Then the 

 larva is soaked in hot water to remove the potash, then 

 transferred to a small dish of alcohol. Under the dis- 

 secting microscope the alimentary canal is cut off square 

 a short distance behind the larva and a glass tube, drawn 

 out to a fine point, inserted. When we take the larva 

 out of the alcohol Ave find that the rectum soon dries to 

 the tube, making tying-on unnecessary; or, the larva can 

 be tied on in the usual manner. The inflating of these 

 small larvie takes only a feAV minutes. Then the glass 

 tube is broken oft' a half inch or more behind the end 

 and inserted into a piece of Polyporus pith ; this is then 

 mounted by means of a second pin, to make a very neat 

 double mount. 



The larger caterpillars, when blown, are not removed 

 from the straw, but mounted by means of a pin througli 

 it. Now it often happens that this straw splits, and 

 also, the thin walls of the straw do not give sufficient 

 hold on the pin so that the mounted caterpillar has a 

 tendency to fall away at the slightest jar. To overcome 

 this difficulty we made several trials while at New 

 Hanover, and Mr. Haines found that the petioles and 



