08 MR. J. LUBBOCK ON THE DEVELOPMENT OF 
and is continually jerked upwards, even so much as to throw the caudal sete in front 
of the head, which gives the young insects a singular resemblance to the caterpillars of 
the Puss-moths. I have especially noticed that this movement takes place when any still 
minuter creature touches the young Chloéon; the tails, therefore, most likely serve as 
organs of defence, but perhaps also partly for sensation. The larger larvee never bring 
them forward over the body, perhaps because the continual vibration of the branchice 
renders such a movement unnecessary. 
In moulting the insect does not split the skin of the thorax, as is so generally the case, 
but merely that on the upper part of the head. It is wonderful, indeed, how it can escape 
through so small an orifice. 
Second State (fig. 2). 
A specimen, which I met with in the above-described condition on the 21st September, 
had undergone a moult by the following morning. From the analogy of subsequent 
development, it is most probable that the first state lasts only two or three days at most. 
In the second state the total length is still only ths. The general form of the 
body is the same as before; but the posterior angles of the second and four following 
segments are, especially those of the third, fourth, fifth, and sixth, more strongly produced. 
The antenne (fig. 19) are 3! ths in length, but they consist of only the same number of 
segments as before. The first two and the last ten, moreover, have scarcely increased in 
size; but the third, which in the first stage was only 44555ths in length, has about doubled 
itself. We shall presently see how great a part this segment takes in the subsequent 
development of the organ. 
The tarsi have two * supporting " hairs. 
The two tails have increased to a length of ths, and consist of twenty segments. 
Here again, as in the antennz, almost the whole change has taken place in one segment, 
which, however, is in the present case the basal one. The remainder are almost exactly 
as they were before. As already mentioned, the basal segment was in the first stage 
sooths in length; in the present it has divided into two segments, which, taken together, 
are sgoths ; and we see therefore that almost the whole increase of length is in this one 
part. The second segment is somewhat shorter than the first. The minute ridges 
surrounding the basal segment have almost disappeared. 
Between the two tails is a minute knob, which, as we shall see, is destined to become 
_ far more important than its present appearance would indicate. 
The whole skin of the insect, including not only that of the body, but also the antenne, 
legs, and caudal appendages, is beset with little teeth, which fall more or less into 
regular rows. The last row on each segment consists of teeth much larger than the 
others, and forms a sort of fringe of spines. This applies not only to the body, but also 
to the legs and basal part of the antennz and tail. On the segments of the body, these 
spines are most distinct on the central part of the dorsal margin, and especially on the 
deme segment, where also two or three of the spines are much larger than the rest. 
"A NEN of the body are several small circles, which look almost like holes, 
cannot explain the function. In very young larvz they are few in 
