BULLETIN 39, UNITED STATES NATIONAL MUSEUM. [70] 



first two fingers of the left hand and the pin be carefully thrust through 

 at the proper angle. In pinning all insects the pin should be so inserted 

 that the insect is nearly at right angles with the pin, the posterior end 

 being slightly depressed. 



Moanting on Points. Most insects which are too small to be pinned 

 on a No. 2 pin may be fastened to cardboard by means of gum traga- 

 canth, gum shellac, or any good glue. It is not always easy to determine 

 whether to pin a medium specimen or to glue it to a triangle. Pinned 

 specimens are more secure, and not so apt to fall or be knocked oft', 

 but they are liable to become corroded by verdigris and ultimately lost, 

 especially in families the larvre of which are endophytous or internal 

 feeders. It is better to glue wherever there is doubt. A drop of cor 

 rosive sublimate added to the water in which the gum tragacanth is 

 dissolved will indefinitely prevent its souring, but should not be used 

 where the gum is to come in contact with the piu> as it inclines the lat- 

 ter to verdigris. In such cases a little spirits of camphor mixed with 

 the gum tragacanth is best. Shellac should be dissolved in alcohol and 

 this requires some time. This glue is not affected by moisture, and if it 

 is desired to remove the specimens, they must be immersed in alcohol 

 until the shellac is again dissolved. 



A number of different kinds of glue are used by entomologists. 

 The requirements of a good glue are that it be colorless, and. what 

 is of greater importance, that the specimens adhere firmly to the 

 paper points so that there is little or no danger of their being jarred 

 off. Those glues which are readily soluble in cold or lukewarm water 

 are perhaps more convenient than those which require alcohol or chloro- 

 form, for dissolving. Gum arabic and gum tragacaiith have the disad- 

 vantage that they are more liable to attract mites and are more brittle, 

 so that they do not hold specimens as well as some of the liquid glues 

 that are on the market. Spalding's glue answers a very good purpose, 

 as also the preparation known to European entomologists as Leprieur's 

 gum. White bleached shellac, while requiring alcohol to dissolve it, 

 has the advantage that a very minute quantity suffices. In olden times 

 the method employed was simply to glue the specimen by the ventral 

 side to the middle of a quadrangular piece of cardboard, which was 

 then pinned on a No. 3 or No. 4 insect pin. This method is still in 

 vogue with English entomologists, but can not be recommended except 

 for mounting duplicates. Much better are the small isosceles triangles 

 which, before mounting the specimen, are pinned through near the base 

 on a Xo. 2 or No. 3 insect pin. Only the best and finest cardboard 

 should be used for this purpose, since that of poor quality is liable to 

 ,e broken while passing the pin through it and will yellow with age. 

 l - Keynolds's Superfi.no Mowd," which may be ordered through any 

 dealer in artist's supplies of Devoe & Co., Fulton street. New York 

 City, is perhaps the best lor this purpose. Some of the neatest mount- 

 ing which I have had done by any of my agents or assistants is by Mr. 



