OF EPPING FOREST. 285 



Another method of exhibition, which has been made 

 use of at the British Museum, is the preparation of coloured 

 wax models of the galls and of the plants upon which 

 they grow. As regards oak galls, such as Trigonaspis crustalis, 

 both generations are shown in the same case, Trigonaspis renum 

 appearing on the leaves and T. crustalis from the adventitious 

 buds on the trunk. There is often a tendency to depict "good 

 specimens " by exaggerating the size and number of the galls, 

 and this should be guarded against as giving a wrong impression 

 to anyone who is just starting to collect, who is not always quite 

 certain what to look for. [I have found that a solution of 

 formalin (about 5 per cent, of the 40 per cent, commercial 

 formalin) preserves the form of most galls, but any colour 

 dependent upon chlorophyll or its derivatives disappears in the 

 course of time. We are now trying in the museum a method of 

 bleaching with sodium hypochlorite, which discharges all colour 

 and produces a semi-transparency, displaying form and structure 

 excellently well, the specimens being " put up " in 90 per cent- 

 alcohol. Of course, as Mr. Lewis says, such preparations should 

 be placed alongside drawings giving the natural colours of the 

 galls. — W. Cole. J 



Classification. 



Since the discovery by Dr. Adler of the alternating agami 

 and sexal generations among the oak gall-makers, the nomencla- 

 ture has undergone, a change. The method adopted by Mr 

 Cameron is the truly scientific one, but these alternating genera- 

 tions present such variations that the generic names used by Dr. 

 Adler, 5 which serve to differentiate more clearly between the 

 agamic and sexual forms, are still adhered to in many cases. I 

 have, therefore, inserted a list showing the differences between 

 the nomenclature of these two authors. 



In the case of the three forms, Andricus feciindatvix , Andriciis 

 malpighii and Dryophanta divisa, I have found galls of the agamic 

 generation only, and have been unable to find specimens of the 

 corresponding sexual generations, Andricus pilosus, A. niidus and 

 Dryophanta vcrucosiis xes^ectvjeXy, so that in this list these latter 

 have been printed in italics. I have inserted them partly because 

 in giving an account of the generation cycle they must necessarily 



5 Alternating Generations. A Biological Study of the Oak Galls and Gall Flics. By 

 Hermann Adler, M.D., Schleswijj. Translated and Edited by Charles R. Straton. F.R.C.S., 

 F.E.S. Oxford 1894. _ 



