28 EIO DE JANEIRO. [CHAP. n. 



quarter of a mile, and was like the rushing of a great body of 

 water. After the hotter days, it was delicious to sit quietly in the 

 garden and watch the evening pass into night. Nature, in these 

 climes, chooses her vocalists from more humble performers than in 

 Europe. A small frog, of the genus Hyla, sits on a blade of grass 

 about an inch above the surface of the water, and sends forth a 

 pleasing chirp : when several are together they sing in harmony 

 on different notes. I had some difficulty in catching a specimen 

 of this frog. The genus Hyla has its toes terminated by small 

 stickers ; and I found this animal could crawl up a pane of glass, 

 when placed absolutely perpendicular. Various cicidse 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, nereida3, 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 number of specimens were 

 of Lampyris occidentalis.* I found that this insect emitted the 

 most brilliant flashes when irritated : in the intervals, the abdomi- 

 nal rings were obscured. The flash was almost co-instantaneous 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 



* 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. 



