PRESERVATION OF EGGS OF DIPTERA 417 



the hole in the cork is then rapidly plugged with a pledget of wool and the 

 cork sealed at once by dipping it in melted paraffin. In this way 

 specimens can be kept in a dry condition in any climate. When 

 it is desired to examine them the cork is removed, and when the 

 specimens are replaced in the tube it is again placed in the desiccator for 

 a few days and sealed as before. This is the method recommended by 

 the Central Malarial Bureau at Kasauli for the preservation of mosquitoes. 

 If it is desired to keep more than one specimen in the same tube, the 

 flies should be pinned to a strip of thick cork, say two and a quarter by 

 half an inch, one end of which is cut out in order to secure it to the cork 

 of the tube with a pin. As before the cork of the tube has a wedge- 

 shaped piece cut out so that the specimens may be dried and the tube 

 sealed. Text figure 2, which is copied from a paper in Palitdism by 

 Major Christophers, I. M.S., shews this method of preserving mosquitoes. 



of CorK 



TEXT FIGURE 2 



For cutting out card discs it is convenient to have a gun wad punch, 

 size No. 12 or No. 20. These discs are very useful for mounting 

 mosquitoes which are to be put up in tubes. A very fine pin should be 

 used, and passed through the thorax from the ventral side. The head of 

 the pin is then cut off with a slanting cut, and the sharp end left is 

 inserted in the disc, and held in place by a drop of sealing wax on the 

 reverse side. 



The preservation of the eggs of diptera in a condition suitable for 

 study is a difficult matter. They do not make satisfactory or permanent 

 preparations if mounted in glycerine, Farrant's solution 

 or Canada balsam. The problem appears to be solved, Preservation of 

 i xr T TVJ c u i ji early stages of 



however, by Major Perry, I. M.S., who very kindly Diptera; eggs 



shewed the authors his method as applied to the eggs 

 of mosquitoes. The eggs are placed in five per cent, formalin and drawn 

 up from it into a glass tube, the calibre depending on the size of the 

 53 



