CXIT 
greatly developed hind-legs in the male, of the short antenna, and 
the conspicuously five-jointed tarsi. 
I regret that I can not make any suggestion as to the function of 
the extraordinary hind legs. It is clear they do not serve for ordi- 
nary locomotion, and they are pretty certainly in walking merely 
dragged along the ground, the peculiar apical prolongation of the 
tibia preventing the pubescent apex from touching the ground, 
while the tarsus is turned upwards and applied to the back of the 
tibia in the peculiar groove provided for the purpose, so that it is 
out of the way and not likely to catch in surrounding objects. 
Whether the legs take à part in the process of copulation, or 
whether they assistthe males in their combats — either as weapons 
of offence or defence. — I am quite unable to conjecture. 
I expect the males of this insect are for a brief season abundant 
in numbers in the locality they inhabit, but probably they are 
chiefly nocturnal in their activities; and probably their life in the 
perfect stateis a very short one. 
IfI am correct in my suppositions about this insect, those of us 
who are evolutionists, will have to admit that the organisation of 
this extraordinary creature has been evoluted in correlation with 
its sexual combats, through a long series of ages, and there has 
thus resulted a most extraordinary perfection of the structures 
directly and indirectly connected with this object. This is so 
abhorrent to our moral sense that we may well feel gratified that 
we can also point to the fact that these structures are unique, and 
that out of hundreds of thousands of insects now known to us 
there is nothing to indicate that any other has passed through a 
similar evolutionary record. 
M. le D' Jacobs donne lecture des notes suivantes : 
PREMIER SUPPLÉMENT 
AUX TENTHRÉDINES, CÉPHIDES ET SIRICIDES 
DES ENVIRONS DE BRUXELLES 
par le Dr J.-C. Jacobs. 
Phyllotoma Aceris Kaltenbach. 
Juin, Juillet. — La larve sur l’Acer campestre L. 
Pris en abondance par M. Mac Lachlan sur différentes 
espèces d’Acer exotiques, dans le jardin de la campagne 
de M. Van Volxem, à Vilvorde. 
D’après les observations de notre collègue, la larve ronge 
la partie inférieure de la feuille, ce qui laisse des taches 
