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MOXOGEArn OF THE LAB0ULBENTACE.'T5. 219 
to be possible, which I very much doubt, arc not likely to alTord data which could not 
be as well or better observed by the examination of .sncccssive stages in Individual! 
naturally developed; except, perhaps, in so far as concerns the possibilllus of mou- 
strous development which these plants might exhibit under such unnalural condition''. 
Preparation of Material for Exaiuuiation. Having ol)tained a nnnib-T of Iiosts 
whicli are liable to be parasitized, it will found that from about five to fifty per cent, 
will bear parasites. In order to obtain them for examination, the host .should be 
killed and impaled on a fine needle (a No. 12 sewing-nccdlc mounted in a match Is 
the most convenient), care being taken that the surface of the insect remains perfectly 
clean and dry, and then examined over a dull white, and then over a black surface 
with a hand lens magnifying about eight or ten diameters, a dissecting microscope 
being most conveniently used for this manipulation. Every portion of the insect 
should be examined in different positions, and when the parasites have been dis- 
covered, they should be removed by means of a dissecting needle like that just men- 
tioned, the needle having been inserted in the match far enough to give it the 
requisite stiffness, while its apex should have been ground on ' a fine oil-stone 
until a sharp, slightly oblique chisel point has been obtained. With .'^uch a ]>oInt, the 
individuals are scraped off without much difficulty, and should be transferred to a very 
small drop of water on the slide. When the desired number liave been thus trans- 
ferred, the individuals may be conveniently arranged by means of a fine hair mounted 
like the needles. The excess of water should thm be drawn away from the spooi- 
mens with a shred of blotting paper, and as soon as the moisture has dried around 
them, they should be quickly treated with alcohol, and covered with a cover gla8.s 
which should always be supported by a shred of blotting paper or a chip of cover 
glass.- The alcohol should then be replaced by water, n^ quickly as possil)le, when 
the individuals will be found still living, if the manipulations have been sufficiently 
rapid, and attached to the surface of the slide as a result of the slight drying just 
mentioned. Although these directions may seem superfluous, it will be found that if 
they are accurately followed, much trouble and the loss of many specimens will l)e 
avoided. For permanent mounting, 1 have used only glycerine, to which is best added 
,11 nmonnt of a saturated alcoholic solution of eosin, together with a trace of 
a sm 
common 
salt. This preparation is very satisfactory for general purposes, and should 
be allowed to run under the cover glass and replace the water slowly, as it evaporates. 
If the replacement is too rapid, the individuals will become shrunken, but generally 
re<]rain 
their normal form In a few days, or in a much 
Dried material for herbarium specimens, which is always sufficiently good for 
