BULLETIN 39, UNITED STATES NATIONAL MUSEUM. [86] 



when mounted tliese appendages can readily be studied. If mounted 

 living, tlie legs are almost invariably curled up under the body and can 

 not be seen. This method may also be used in the case of other minute 

 insects. Some insects, such as minute Diptera, are injured by the use 

 of hot water, and for these dipping in hot spirits is recommended. 



In the mounting of Aphides the same difficulty is avoided in a meas- 

 ure by Mr. G. B. Buckton, author of "A Monograph of the British 

 Aphides," by first placing a few dots of balsam on the glass slide, to which 

 the insect is transferred by means of a moistened camel's-hair brush. 

 The efforts of the insect to escape will cause it to spread out its legs 

 in a natural position and a cover glass may then be placed in position 

 and a drop of the balsam placed at the side, when, by capillarity, it 

 will fill the space between the slide and cover glass and the limbs 

 will be found to have remained extended. If three or four drops of the 

 balsam are put on the glass the wings may also be brought down and 

 caught to them so that they will remain expanded in shape for ex- 

 amination. 



Preparing and Mounting the Wings of Lepidoptera. — The student of 

 Lepidoptera will frequently find it necessary in the study of the vena- 

 tion of wings to bleach them or denude them of their scales in some 

 way. Yarious methods of bleaching and mounting the wings of these 

 insects have been given, and a few of them may be briefly outlined. 



The simplest and quickest, but perhaps the least satisfactory, method 

 is to remove the scales with a camel's-hair brush. This will answer for 

 the larger forms and where a very careful examination is not required. 

 For more careful examination and study the wings are first bleached 

 by the action of some caustic solution and then mounted in balsam for 

 permanent preservation. Chambers's method for Tineina, Tortricina, 

 Pyralidina, and the smaller moths generally, is as follows : The wing is 

 placed on a microscopic slide in from 3 to 4 drops of a strong solution 

 of potash, the amount varying according to the size of the wing. A 

 cover of glass is then placed in position on the wing as in ordinary 

 mounting. 



The quantity of liquid should be sufficient to fill the space beneath, 

 but not sufficient to float the cover glass. The mount is then placed 

 over an alcohol flame, removing it at the first sign of ebullition, when 

 the wing wiU be found denuded, if it be a fresh specimen. An old 

 specimen, or a larger wing, will require somewhat more ijrolonged 

 boiling. The fluid is drawn off by tilting the glass or with bibulous 

 paper, and the potash removed by washing with a few drops of water. 

 The cover glass is then removed and the wing mounted either on the 

 same slide in balsam or floated to another slide, or at once accurately 

 sketched with the camera lucida. Permanent mounting, however, is 

 always to be recommended. 



The Dimmock method of bleaching the wings of Lepidoptera, given in 

 Psyche, Vol. i, pp. 97-99, is as follows : He uses for bleaching a modifica- 



