318 ENTOMOLOGY. 



ganglia, and the brain are in this way finely shown, the brain reveal- 

 ing the very abundant ramifications of the tracheae, especially the im- 

 mense parallel branches situated between the rods of the eyes. 

 {Psyche, iv. 253.) 



Mounting Legs, etc., of Insects. — Mr. II. A. R. Bennett, in regard 

 to this topic, which will also apply to large antennae, palpi, etc., 

 remarks: The chief difficulty is the appearance of air-bubbles in the 

 object after it has been mounted. To avoid this, there is a little 

 dodge not mentioned in most books. When the leg is taken out of 

 the turpentine, instead of placing it at once on the slide, boil it for a 

 few moments in some balsam, kept for the purpose in another tube. 

 While it is being boiled the air will escape, and the balsam will take 

 its place. There will therefore be not nearly so much chance of air- 

 bubbles arising when the object is mounted. Of course this would be 

 rather rough treatment for some objects; but with the legs of insects 

 (especial by such as Dytiscus marginalia) it generally answers admirably, 

 and saves a vast deal of trouble. (English Mechanic, 1883, 253.) 



Mounting the Skin of Caterpillars. — E. E. Jackson soaks the speci- 

 men in acetic acid for ten days, then opens the body carefully with 

 scissors from anus to mouth, and washes it in water. He then soaks 

 it in weak, afterwards in strong, alcohol, following with oil of cloves, 

 turpentine, and balsam. (The Microscope, 1884, 133.) 



Dissection and Preparation of the Spermatic Filaments. — F. R. 

 Cheshire proceeds in the following manner: " Secure a drone (not 

 newly hatched) as lie is perambulating the combs, open the body, re- 

 move the vesicula, break one end, and. with the forceps, apply for a 

 moment the ruptured part to the surface of some glass covers upon 

 which a small quantity of water has been placed (one vesicula will 

 give a supply for a dozen slides); leave to dry, keeping from dust; 

 warm in the flame of a spirit-lamp to set the albumen, pour on each 

 three or four drops of watery solution of Bpiller's purple, and alter 

 five minutes wash, dry, and mount in Canada balsam. For critical 

 examination with high powers, spermatozoa should be mounted in 

 glycerine. If staining be desired, a minute quantity of the purple 

 added to the glycerine will accomplish it, as in a few weeks the sper- 

 matozoa will have absorbed every trace of the dye. ("Bees and 

 Bee keeping," 201.) 



Prof. v. la Valette St. George recommends, for the examination of 

 the spermatic elements of the small cockroach (Blotto germaniccu or 

 Croton bug) a fluid which unites I lie properties of not being harmful 

 to cells and that of staining certain cell-parts deeply. This is iodized 

 serum, rubbed in with dahlia and filtered. The amniotic fluid can 

 thus be replaced by another indiherent fluid. Dilution of pure 

 nuclear-staining media with iodized serum did not give favorable 





