( xxv) 
marked. The resemblance between the ‘simplex’ form of 
the male (e) in which the hind-legs are practically unmodified, 
there being neither angulation near the base of the tibia nor 
production inwards at the apex of that member, to the female - 
of Grammoptera ruficornis is in life particularly striking, the 
proportion of the Osphya to the Longicorn being approxi- 
mately two per cent. 
“T have kept a number of living specimens of both sexes 
of Osphya in confinement, and had ample direct evidence of 
one important function of the hind-legs of the male, namely, 
to secure him in position at the time of pairing. He mounts 
the back of the female, who struggles to escape, and seizes her 
with his mandibles by the neck, clasping her in the meantime 
round the body with his front pairs of legs whilst the hinder 
pair are so adjusted that the hind tibiz of the female are held 
between his femora and tibie near the knee-joint (that is, 
between the joint and the small tooth on the femora), and the 
remainder of the inner edge of his hind tibie is closely applied 
to the venter of the female abdomen; the large curved tooth 
at the apex of the tibia fits the curve of the under-surface of 
the female abdomen and evidently serves to increase the grip. 
The effect of these circumstances is to secure the pairing of 
individuals of suitable size, for the small males were quite 
unable to hold the large females whilst the small females 
escaped with ease from the embrace of the normal males. It 
appears remarkable that the small form is not more common, 
as I observed the males to pair readily enough with females 
of suitable size. I found no evidence in support of the theory 
that the strongly modified hind-legs of the normal males serve 
to give the insects a better grip of their support under ordinary 
circumstances ; on the contrary, during ordinary progression 
the hind tibia is closely applied to the femur, the tip of the 
inward prolongation at the apex of the former locking into 
a cavity in the trochanter and leaving only the tarsus free.” 
Mr. H. Sr. J. Donistuorre expressed his opinion that the 
resemblance between the forms was most certainly protective, 
and Mr. A. J. Cuirry said that in Monkswood, Hunts., where 
he had taken Osphya in abundance, all the females belonged to 
the light form, 
