II PHOSPHORESCENT INSECTS 31 



lutely perpendicular. Various cicadae and crickets, at the same 

 time, keep up a ceaseless shrill cry, but which, softened by the 

 distance, is not unpleasant. Every evening after dark this great 

 concert commenced ; and often have I sat listening to it, until 

 my attention has been drawn away by some curious passing insect. 

 At these times the fireflies are seen flitting about from 

 hedge to hedge. On a dark night the light can be seen at 

 about two hundred paces distant. It is remarkable that in all the 

 different kinds of glowworms, shining elaters, and various marine 

 animals (such as the Crustacea, medusae, nereidai, a coralline of 

 the genus Clytia, and Pyrosoma), which I have observed, the 

 light has been of a well-marked green colour. All the fireflies, 

 which I caught here, belonged to the Lampyridae (in which 

 family the English glowworm is included), and the greater num- 

 ber of specimens were of Lampyris occidentalis.^ I found that 

 this insect .emitted the most brilliant flashes when irritated : 

 in the intervals, the abdominal rings were obscured. The 

 flash was almost coinstantaneous in the two rings, but it 

 was just perceptible first in the anterior one. The shining 

 matter was fluid and very adhesive : little spots, where the skin 

 had been torn, continued bright with a slight scintillation, whilst 

 the uninjured parts were obscured. When the insect was 

 decapitated the rings remained uninterruptedly bright, but not 

 so brilliant as before : local irritation with a needle always 

 increased the vividness of the light. The rings in one instance 

 retained their luminous property nearly twenty-four hours after 

 the death of the insect. From these facts it would appear prob- 

 able, that the animal has only the power of concealing or 

 extinguishing the light for short intervals, and that at other 

 times the display is involuntary. On the muddy and wet 

 gravel - walks I found the larvje of this lampyris in great 

 numbers : they resembled in general form the female of the 

 English glowworm. These larvae possessed but feeble luminous 

 powers ; very differently from their parents, on the slightest 

 touch they feigned death, and ceased to shine ; nor did irrita- 

 tion excite any fresh display. I kept several of them alive for 

 some time : their tails are very singular organs, for they act, by 

 a well-fitted contrivance, as suckers or organs of attachment, 



1 I am greatly indebted to Mr. Waterhouse for his kindness in naming for me 

 this and many other insects, and in giving me much valuable assistance. 



