of Prague. In answer to an enquiry, Ilerr Fric tokl ine that bis 

 curiosity bad also been aroused, and that be bad vainly tried to learn 

 tbeir nature from tlie collector, an old man, who, from bis silence, was 

 probably dead. It was, therefore, necessary to make out the nature 

 of the substance from examination of the blocks, and this investigation 

 proved successful. 



The stages w^erc made of the felted mass of a fungus-fructification 

 (strictly, the hymenophore of Polyporus hetulinus). This material is 

 as nearly as possible perfect ; when of good quality it is pure white, 

 dense and even in texture, without holes, flaws or hard places. It can 

 be cut into any desired size, and when smoothh^ cut has a surface 

 almost resembling that of fine plaster. It admits the very finest pins 

 without turning the points, and it holds the pins firmly, which pith 

 will not do. If fresh, or slightly moistened by a sojourn in the 

 relaxing box, it is tough and cuts smoothly, when quite dry it is harder 

 to cut and is slightly friable, though not materially so. When wetted 

 it becomes soft and s[)ongy, and a pin fixed in it can be easily released 

 by applying a brushful of water round the insertion. 



As to its lasting qualities, pieces used in Zeller's collection, which 

 must be many years old, show no signs of deterioration, nor have they 

 corroded the pins in any way. It has been suggested that the fungus 

 may encourage the growth of mites or mould. This there is no reason 

 to suspect ; though it absorbs moisture and will grow mouldy if kept 

 damp, it does so only under conditions in which the insects themselves 

 would be injured. 



As it is not obtainable everywhere, and special aj)paratus and 

 some skill are required to cut it uniformly and without waste, Messrs. 

 AVatkins and Doncaster have undertaken to supply it. The difiiculty 

 of cutting has been fairly well surmounted, and the material will be 

 sent out in strips which can be divided transversely into the required 

 lengths with a very sharp knife (such as an old table knife well ground). 

 An ounce of strips will mount from 700 to 1500 or more specimens, 

 according to the size of stage required. They should be handled as 

 little as possible, as they easily show finger marks or force[)s dents. 

 The latter will come out if the strip is placed for an hour or two in a 

 relaxing box, after which it cuts better; but it must not be allowed to 

 touch the moist surface, or it will be spoiled. 



A drawerful of small Lrpidopfcra carefull}' staged on this material 

 looks extremely neat ; that the specimens are more secure against 

 injury, and that the value of the collection is thereby increased, can 

 hardly be disputed. 



