Regeneration of the Tarsus in Phasmide. 509 
with rust-coloured bands forming equidistant rings round the 
body and legs. The latter have a mean length of 8 millim. 
One would therefore at first be tempted to suppose that the 
smallest difference in length between two limbs of the same 
pair—the one normal, the other regenerated after autotomy— 
could not be less than this number of millimetres. Under 
these conditions how are we to suppose that a limb has been 
regenerated after autotomy, because its length is less by 
scarcely 3 or 4 millimetres than that of the corresponding 
limb? I succeeded nevertheless in assuring myself by experi- 
ment that the thing was possible. In order to do this I 
provoked autotomy in a larva which had just hatched. The 
amputated leg measured 8 millim. and was of precisely the 
same length as the limb opposite to it. A prioré one might 
therefore suppose that the regenerated limb would always be 
shorter by at least 8 millim. than the one which had remained 
intact. However, immediately after the first moult, when the 
larva had just quitted its skin, I perceived the regenerated 
limb forming a little spiral, which unrolled itself after a few 
days and assumed the appearance of the other legs. The 
length of this regenerated limb was between 7 and 8 millim., 
so that the limb opposite to it, having increased by only 
3 millim, and then having a length of 11 millim., the difference 
between the two legs was little more than 3 millim. There 
is therefore a difference between the rate of growth of the 
normal limb and the rate of growth of the limb in course of 
regeneration, this latter growing more rapidly. This pheno- 
menon certainly affords the interpretation of the doubtful 
case that I mentioned at the beginning of this communication. 
The question may arise whether the variation in the 
number of the joints of the tarsus is always a consequence of 
amputation by autotomy or whether it is sometimes con- 
genital. Although hitherto I have never seen tetramerous 
tarsi in larve of Phasmide examined immediately after birth, 
tetramery might nevertheless very well be observed in the 
young on emerging from the egg, and consequently without 
having been preceded by the slightest mutilation. 
So far from regarding autotomy as a relatively recent 
improvement, I should, on the contrary, be disposed to believe 
that in primary ages certain groups of insects already benefited 
by the advantages of this protective process. If, indeed, ve 
examine carefully certain of the drawings given by M. Ch. 
Brongniart in his handsome memoir on primary insects 
(‘ Recherches pour servir 4 V’histoire des Insectes fossiles des 
temps primaires,’ 1893), and especially the figures of pl. xlix. 
and fig. 1 of pl. xxxvil., we notice in the limbs an arranges 
