128 
THE YOUNG SCIENTIST. 
But the young botanist who does not 
"wish to have a good deal of trouble thrown 
away, and to see his well dried specimens 
devoured by insects, has more work before 
him yet. Mould is not likely to trouble 
him with plants which have once been 
made completely dry. A botanical friend, 
to whom I am indebted for several of these 
hints, writes: "At one time, in the very wet 
summer of 1875, and when I had my press 
so full that scarcely more than two sheets 
were between plant and plant, I found, to 
my disgust, many of them moulding. But 
I took heart, and brushed off the mould 
with a moderately stiff brush continually, 
till they were thoroughly dry, and then 
stacked them away between dry sheets, and 
did not look at them again till nine months 
afterwards, when I found them without a 
particle of mould. Later on, I cured some 
of the mould by brushing it off and wash- 
ing the plants with corrosive sublimate, 
while they were still in the press. But, by 
pressing few at a time, and by using more 
paper, I might, of course, have escaped 
that; and it does not do to trust to being 
able to get rid of the mould so, for it dis- 
colors the specimens." But all plants are 
more or less liable to the attacks of insects, 
and some, as the RanunculacecB, Cruciferee, 
and Umhelliferoe, especially so. The best 
preventive is corrosive sublimate. The 
Rev. Gerard Smith recommends dipping 
Ranunculacece (buttercups) and Cruciferee 
(shepherd's purse, cuckoo-flower, etc.) be- 
fore pressing, into a saturated solution of 
corrosive sublimate in equal parts of rain 
water and methylated spirits. A more con- 
venient plan is to paint the specimens with 
the liquid after they are mounted. For 
this purpose a solution should be made of 
one-quarter of an ounce of the sublimate in 
half a pint of methylated spirit (not 
" methylated finish,") which is to be applied 
to the specimens with a pretty stiff brush, 
taking care that it penetrates all corners and 
crevices. Every plant should be treated in 
this way, as it not only prevents the attacks 
of insects in the future, but entirely de- 
stroys any animal life that may be already 
there. The sheets are then to be again sub- 
jected to pressure for twelve hours, after 
which they will be ready for the herbarium. 
It only remains now to arrange the speci- 
mens in proper order, but as it is unneces- 
sary to do this until a large number have 
been collected, we will leave the consider- 
ation of it at present. Meantime the sheets 
should be laid flat in a box, secured from 
dust, kept in a dry place, and not exposed 
to the light more than necessary. — Science 
How to Study Entomology. 
BY r. 0. SMITH. 
IV. 
Continued from page 105. 
\ NSECTS are divided by most naturalists j 
^ into nine orders. These orders are 
again divided into families, and the fami- 
lies into species. 
The orders are as follows r Aptera, Dip- 
lera, Hemiptera, Lepidoptera, Orthoptera, j 
Hymenopiera, Thysanoptera, Neuroptera and I 
Goleopiej^a. 
Insects of the order Aptera are wingless, ^ 
and embrace fleas, lice, etc. All insects j 
which suck their food, and possess but twa 
membranous wings are called Diptera. 
Most insects of this order have two very 1 
minute appendages, in the absence of the ! 
second pair of wings, called poisers, their I 
duty being to regulate the flight of the in- i 
sect. The Hemiptera are four winged, itt | 
some species membranous, and in others i 
the upper wings are of a harder consist- I 
ency than the lower. The order Lepidop- 
tera embrace the insects commonly known ! 
as the butterfly and moth. These insects \ 
are remarkable for their beautiful colors, 
and are found in great variety in all parts i 
of the world. They undergo three comr \ 
plete transformations. Cockroaches, lo- 
custs, grasshoppers, crickets, etc., are of 
the order Orthoptera. The anterior wings 
are usually long, narrow, and half horny, 
and serve only as a protection for the sec- 
ondary wings, which are more delicate and 
used for flying only. The metamorphoses 
