THE SUBSTITUTE. 
163 
lavvse were taken on the Gog and 
Magog hills (about 4 miles hence), 
and were brought to me in that 
state. I purchased them after 
they changed to chrysalides (Oc- 
tober 11). I had determined to 
force out the inseeis by heat to 
avoid the risks of accident during 
a long winter, and all my friends 
and. fellow-coljectors here pre- 
dicted, for my encouragement, my 
total failure, as I was going to try 
a novel way of forcing. I need 
not say that the appearance of two 
splendid specimens of Galii has 
changed dieir opinion consider- 
ably. My plan w-as this: — I had 
two square tin cases, like boxes, 
without covers, the one an inch 
wider each way, and two inches 
deeper than the other;- of these 
the smaller contained the chrysa- 
lides lying on moss and covered 
up with a thick layer of the same ; 
this was always kept damp. Over 
this tin was a frame covered with 
net to prevent the escape of the 
insects: this tin was supported 
inside the layer, so that the tops 
of the two were level. The larger 
tin was then filled with water, 
which was kept hot by a small 
spirit-lamp underneath: this kept 
the temperature regular, the 
water being about 80° or 90° 
(Fahrenheit), while the chrysalides 
were, on the average, about 70°. 
I see from my Journal that the 
earliest date on which T obtained 
any chrysalides of Atrofos is 
September 22, three Atropos ; 
September 23, four Atropos ; Sep- 
tember 27, three more, &c. ; Octo- 
ber 11, two D. Galii. As I was 
then expecting more chrysalides 
to be brought I deferred putting 
the case in hot water, till I was 
disagreeably surprised by the ap- 
pearance of one crippled Atropos, 
November 7th, and three more on 
the 14th. I then 
commenced 
burning the lamp, and had no 
more deformed specimens. The 
following is a table of the dates 
of the appearance of the insects: — 
1 crippled . . . 
Nov. 7 
3 „ . . . 
,, 14 
1 perfect Atropos . 
„ 18 
f 5, J> • 
„ 25 
2 ,, ,> • 
„ 29 
d 5, »» • 
Dec. 8 
3 » M • 
„ 9 
)» • 
„ 10 
2 „ „ Dec. 
14 or 15? 
f 5, )5 . • 
Dec. 17 
f . 5» 
„ 20 
1 D. Galii . 
. » 20 
f »» ii • 
„ 31 
I feel no doubt that had I com- 
menced earlier the addition of 
heat I should have had no crip- 
ples. I was absent on the 20th 
and 2lst November, and my ser- 
vant was irregular in attending to 
the lamp: to this I attribute the 
loss of twelve pupse, which I sub- 
sequently removed, in which the 
insect was perfectly formed. As 
the heat was not then kept regu- 
lar, I think that it was not suffi- 
cient to stimulate the insect at 
that critical time. I can add no- 
thing, I regret, to elucidate the 
origin of the noise made by this 
insect as to whence it comes, and 
whether purely vocal or mechani- 
cal. All of my specimens squeaked 
very loudly, except the last, which 
could not by any amount of wor- 
rying be made to cry. Nature 
seemed not to have gifted it as the 
rest of its fraternity, and the 
closest examination Jailed to de- 
tect any external difference. I do 
not agree with a former corres- 
pondent in thinking that the case 
