THE ENTOMOLOGIST. 867 



Food of the Ailanthus Silkworm. — M. Hignel, the manager 

 of the silk-culture establishment of Siclae, in the neighbour- 

 hood of Warsaw, noticed that some of his larvae, which had 

 fallen accidentally from the Ailanthus on to a poisonous 

 plant, Datura Stramonium, growing close by, began to feed 

 greedily on its leaves, and on being returned to the Ailanthus 

 refused to spin. Next year M. Hignel intends to try this new 

 food for this silkworm, which is now completely naturalized 

 at Warsaw, and will publish the result of his experiments. — 

 Bembowski, ' Petites Nouvelles Enlojnologiques^ February 

 15, 1873. 



[It will place the cultivation of this silkworm within the 

 reach of everyone if the Datura answers the purpose, for it is an 

 annual which grows so freely in all our gardens as sometimes 

 to become a troublesome weed. — E. Neivman.'\ 



Method of Preserving Insect-pins from Oxidation. — 

 Entomologists, and especially those who collect the smaller 

 insects, and cannot, as in the instance of the Micro- 

 Lepidoptera, gum them on cards, are annoyed with the 

 oxidation of the pins, which so often involves the loss of 

 Entomological collections. Many plans of obviating this 

 difficulty have been suggested and tried, more particularly 

 the use of silver and platinum wire, and of the varnished 

 Vienna pins. For minute insects platinum wire is certainly 

 the best. The objection to the large varnished Vienna pins 

 is to be obviated by the following process, which has the 

 additional recommendation of being extremely simple. 

 Having furnished myself with a colourless varnish, capable 

 of resisting the oxidation of metals, I take hold of the pin 

 near its point with the forceps, and dip it in the varnish from 

 the head as far as the place where the forceps hold it, so that 

 the point may not be wetted with the varnish ; then turning 

 the end I stick it on the cork. When I have served a suffi- 

 cient number of pins in this way I repeat the operation, so 

 that the coat of varnish may be rendered thicker. This 

 operation being performed cold, the pin retains its elasticity, 

 whereas by the German method, of using black varnish and 

 linseed oil, and baking the pins in a hot oven, the wire 

 becomes rigid, and loses its elasticity. The colourless 

 varnish has, moreover, the advantage of being perfectly 

 invisible. I am indebted to Mr. Gogordau for the knowledge 



