AND THE DEVELOPMENT OF THE MYRIAPODA. 
123 
a temperature of the surrounding 1 medium, as the last few days had been exceedingly 
warm, and at the time of making this observation the temperature of the atmo- 
sphere was 73° Fahr., and was not lower than 72° Fahr. during the whole day. I am 
greatly inclined to think that the elevated temperature of this and the following day, 
very much accelerated the subsequent changes in some of the specimens. 
On the twenty-ninth day (fig. 17.) the temperature ranged between 67° and 70° Fahr. 
The young Iulidae were now moving about very briskly, with their antennae in con- 
stant motion. They now partook very freely of food, which consisted of the nutri- 
tious matter found by them in the moistened clay in which they were placed. Many 
of them had completely gorged themselves with it, as was evident from the darkened 
and distended state of the alimentary canal and colon, which were distinctly seen 
through the teguments of the body. The warmth and moisture at this period seems 
to have been extremely beneficial to them. Some of them appeared already to have 
acquired their peculiar instinct of burrowing in the clay, as several were very busily 
at work in a little round hole at the bottom of the cell : their bodies seemed also 
to have acquired a degree of strength sufficient for this purpose. The external tegu- 
ment had become of a much darker colour, and assumed the appearance of horn. 
The divisions of all the segments were very distinct. The limbs had acquired much 
strength, and the anal segment was expanded and employed, as before stated, like 
the anal proleg of the larva of Coleoptera. The six new segments had grown very 
much and were fast acquiring their full size, and the germinal membrane at the 
margin of the antepenultimate (13.g) filling the germinal space, was beginning again 
to be developed. The large patch on the seventh segment was now deeper in colour, 
and in a line with this there was a minute spot on each of the five succeeding seg- 
ments, indicating the existence of the foramina repugnatoria (8 to 12.) of Waga, or 
entrance to the little sacs in the body that secrete an offensive fluid. The first of 
these sacs is situated in the seventh segment, its outlet being in the large patch just 
noticed ; and one of them is also developed at the anterior part of each of the suc- 
ceeding segments, to the twelfth inclusive ; but none is as yet seen in the thirteenth 
or last of the new segments, which may be called the germinal segment, and not only 
at the present time, but in each of the succeeding periods, always is more delicate 
than the others, is shorter, and has no repugnatory foramen. The terminal segments 
are still covered with short scattered hairs. The eye now exhibits a peculiar appear- 
ance. The dark circle around it has changed its form, and become somewhat trian- 
gular, and the single ocellus in the centre seems as if formed of several eyes grouped 
together. 
On the thirtieth day I removed the specimens into a new habitation, a small phial, 
the bottom of which was filled with mould, and the top secured by a cork. On 
putting some macerated boiled meat, or animal fibre, into the bottle, they fed most 
voraciously upon it. They had now acquired much strength, and were of a much 
darker brownish colour. The alimentary canal was still seen through the teguments, 
mdcccxli. s 
