MOUNTING PARTS OF INSECTS. 315 



expanded, when a drop of turpentine is applied, a cover laid on the 

 tongue, and a clip applied before the pressure is removed from the 

 tongue. To secure the whole tongue, split one end of a small stick 

 for an inch or so, and holding the split open by a knife blade, place 

 the severed head in the cleft with the top downward, and, withdraw- 

 ing the knife-blade, allow the stick to close upon the head, when it 

 will fully distend the tongue. Now dip the head and tongue in tur- 

 pentine, and leave it immersed for a few days, when it will be found 

 well cleaned, still perfectly distended, and can be released from the 

 stick or cut from the head without danger of its collapsing. Mounted 

 in a cell in balsam, it is a truly beautiful object." (Amer. Month. 

 Micr. Journ., 1884, 12.) 



A. L. Woodward immerses the living fly in alcohol, "and with 

 perfectly satisfactory results. At the moment of death the tongue is 

 forcibly protruded to its entire length. Even the short proboscis of 

 the house-fly is satisfactorily displayed." (Amer. Month. Micr. 

 Journ., 1883, 239.) 



Mr. H. Sharp mounts the lobes of the proboscis of the blow-fly, 

 without pressure, in a solution of biniodide of mercury in one of 

 iodide of potassium (both saturated solutions), which brings out the 

 details of the structure of the pseudotracheae. ' ' I have several pro- 

 bosces of blow-flies mounted in balsam, with and without pressure, 

 but there is nothing to be seen of the membrane in any of them; I can 

 just see it in a glycerine mount, now that I know what to look for; 

 but the glycerine does not make it visible like the mercury solution." 

 (Journ. Roy. Micr. Journ., 1884, 1003; 1885, 733.) 



Microscopic Sections of the Proboscis of Flies, Bugs, and Bees. The 

 excellent work done by Dimmock on the mouth-parts of the mosquito 

 and other flies, by Kraepelin on those of the fly, flea, and Hemiptera, 

 was chiefly by means of microscopic sections. In order to ascertain 

 whether the pseudotracheae of the fly's labella are hollow or not, 

 Dimmock fed the fly with a mixture of sugar and gum arabic, colored 

 with carmine, then plunging it suddenly into strong alcohol to fix the 

 colored solution in its mouth-parts. Mr. Cheshire, before cutting 

 sections of the bees and other honey-feeding insects, recommends 

 that the insect to be operated upon should be kept fasting for some 

 time, and then fed on honey mixed with gelatine impregnated with 

 some highly colored dye; the insect should be immediately decapi- 

 tated, and the head rapidly cooled and then embedded in gelatine, and 

 the section cut by means of the microtome. The mouth-passage is 

 then easily seen from the presence of the dye. 



Sections of the Ovipositor or Sting. According to Mr. J. W. Hyatt, 

 the insect or organ is placed in alcohol until it is thoroughly perme- 

 ated, and then removed to a clear alcoholic solution of shellac, in 



