204 THE ENTOMOLOGIST. 



meters, say half an inch long) should be employed. This is 

 thrust through the scutellum, as in the larger species, and then 

 through a small piece of pith.* Through the other end of the 

 pith is stuck a No. 16 pin. The labels will, of course, be affixed 

 to the larger pin. The male and female (especially when caught 

 in cop.) can be pinned on the same piece of pith. 



It is not advisable to pin Corixce at all, as there is no visible 

 scutellum, and as a very valuable specific character, the strigil, 

 occurs on the dorsal surface of the sixth abdominal segment of the 

 male, the ornamental sex cannot be pinned through the elytra. 

 These insects should, therefore, be affixed with gum or glue to the 

 apex of a small isosceles triangle of cardboard of medium thick- 

 ness, through the base of which is run a No. 16 pin. If possible, 

 the tip of the card should cover only the metasternum or first 

 abdominal segment on one side ; by this method practically the 

 whole insect is available for examination, and, if preferred, it 

 may be adopted in the case of those specimens for which I have 

 advocated the pith staging. Plea, Micronecta, and the smaller 

 Gerridce may be mounted on small oblongs of card, affixed by 

 the ventral surface. Before mounting, the legs (and, in the 

 Gerridce, the antennae) should be thoroughly cleaned and care- 

 fully spread out ; one or two examples of each species should be 

 mounted venter upwards, and one or two on their sides. I must 

 admit that I have not yet found a really convenient fixative ; a 

 good liquid glue is perhaps the best, — the formerly much advo- 

 cated gum tragacanth is an abomination, and should not be used 

 under any circumstances. 



Specimens should be mounted as soon as possible after capture. 



Of course these methods take a much longer time than the 

 older methods of glueing everything down on to card, but the 

 first consideration should be, "What is the best and most 

 convenient mode of preparation to facilitate future study?" 

 Moreover, the heterogeneous appearance occasioned by the 

 different ways of setting, some on single pins, others staged, 

 others on triangular cards, and yet others on oblong cards, will 

 undoubtedly be displeasing to those gentlemen to whom it is of 

 prime importance that every specimen should be at precisely the 

 same distance from the point of the pin, and that the legs in 

 every specimen should be extended at precisely the same angle ; 

 but I hope that any of my readers who may be induced to take 

 up the collection of British Aquatic Bhynchota will do so with 

 the ulterior motive of study. 



A few examples of each species should be preserved in alcohol 

 or formalin, both imagines and "preparatory" stages. The 

 latter will be discussed separately later. 



There should be attached to every specimen at least two 



* Messrs. Watkins & Doncaster sell " Polyporus" pith for this purpose. 



