1832.] BOTANIC GARDEN. 31 



When we were at Bahia, an elaier or beetle (Pyrophorus lu- 

 minosus, Ulig.) seemed the most common luminous insect. The 

 light in this case was also rendered more brilliant by irritation. 

 I amused myself one day by observing the springing powers of 

 this insect, which have not, as it appears to me, been properly 

 described.* The elater, when placed on its back and preparing 

 to spring, moved its head and thorax backwards, so that the 

 pectoral spine was drawn out, and rested on the edge of its 

 sheath. The same backward movement being continued, the 

 spine, by the full action of the muscles, was bent like a spring ; 

 and the insect at this moment rested on the extremity of its head 

 and wing-cases. The effort being suddenly relaxed, the head 

 and thorax flew up, and in consequence, the base of the wing- 

 cases struck the supporting surface with such force, that the 

 insect by the reaction was jerked upwards to the height of one 

 or two inches. The projecting points of the thorax, and the 

 sheath of the spine, served to steady the whole body during the 

 spring. In the descriptions which I have read, sufficient stress 

 does not appear to have been laid on the elasticity of the spine : 

 so sudden a spring could not be the result of simple muscular 

 contraction, without the aid of some mechanical contrivance. 



On several occasions I enjoyed some short but most pleasant 

 excursions in the neighbouring country. One day I went to 

 the Botanic Garden, where many plants, well known for their 

 great utility, might be seen growing. The leaves of the cam- 

 phor, pepper, cinnamon, and clove trees were delightfully aro- 

 matic ; and the bread-fruit, the jaca, and the mango, vied with 

 each other in the magnificence of their foliage. The landscape 

 in the neighbourhood of Bahia almost takes its character from 

 the two latter trees. Before seeing them, I had no idea that 

 any trees could cast so black a shade on the ground. Both of 

 them bear to the evergreen vegetation of these climates the same 

 kind of relation which laurels and hollies in England do to the 

 lighter green of the deciduous trees. It may be observed, that 

 the houses within the tropics are surrounded by the most beau- 

 tiful forms of vegetation, because many of them are at the same 



* Kirby's Entomology, vol. ii., p. 317. 



