Pupae of Lepidoptera, chiefly Lycaenidae. 485 
of giving a mild electric discharge (see p. 376). It is most 
unfortunate that further and more precise experiments 
were not made with these larvae, such as contact with an 
electroscope or voltmeter. A shock such as could be felt 
by the human hand would necessarily be of considerable 
electrical pressure, and for so great a discharge from 
creatures so small as the larvae in question, some elaborate 
development of electroplaxes would be expected. I have 
made numerous sections of the larvae, and at first, not 
being familiar with the immensely thick fibrous cuticle 
possessed by them, I was inclined to suppose that, in 
spite of its lack of resemblance to known forms of electric 
tissue, this unusual structure might be the source of the 
phenomenon. Comparison with some of our native species 
showed, however, that this special cuticle was not peculiar 
to the supposed electric larva. Our own Lycaenid larvae 
such as betulae and quercus are similarly endowed, though 
they do not appear to afford any electric manifestations. 
The cuticle of the larva of témon is extremely rough and 
would therefore cause considerable friction between itself 
and the human skin. In view of this it appeared to me 
that if the larva were capable of producing, when handled, 
extremely rapid muscular contractions or vibrations, an 
effect such as that described might well be produced on 
the delicate tactile nerve-endings of the human skin. 
After theorising in this way, I had the opportunity last 
spring of examining some larvae of 7. prum, which in 
general appearance are not unlike those of tumon. I was 
examining one of them under the stereoscopic microscope 
when I was interested to note that it did in fact “ shiver ” 
at short intervals. The movement was not sufficiently 
rapid to produce an electrical sensation, but it at least 
demonstrated that such muscular vibrations are possible. 
I do not wish to convey the impression that the electrical 
theory is necessarily erroneous, but in the absence of 
tissue having any resemblance to known forms of electro- 
plax, other possibilities should have due consideration. 
The yellowish points which Farquharson regarded as the 
centres of the discharge are almost certainly the chitinanths 
already described. 
e. ON THE PROLEGS OF LYCAENIDAE. 
On the figure of the larva of Tanuetheira timon, Pl. XIII, 
fig. 7, small processes may be observed on the prolegs. 
