234 DARWINISM chap. 



black Tclcphoridse, commonly called "soldiers and sailors," 

 were found, by Mr. Jenner Weir, to be refused by small 

 birds. These and the allied Lampyridie (the fire-fiies and 

 glow-worms) in Nicaragua, were rejected by Mr. Belt's tame 

 monkey and by his fowls, though most other insects were 

 greedily eaten by them. The Coccinellidse or lady-birds are 

 another uneatable group, and their conspicuous and singularly 

 si)otted bodies serve to distinguish tliem at a glance from all 

 other beetles. 



These uneatable insects are prol^ably more numerous than 

 is supposed, although Ave already know immense numbers 

 that are so protected. The most remai-kable are the three 

 families of butterflies — Heliconidae, Danaidae, and Acrceidse — 

 comprising more than a thousand species, and characteristic re- 

 spectively of the three great tropical regions — South America, 

 Southern Asia, and Africa. All these butterflies have 

 peculiarities which serve to distinguish them from every 

 other group in their respective regions. They all have ample 

 but rather weak wings, and fly slowly ; they are always very 

 abundant ; and they all have conspicuous colours or markings, 

 so distinct from those of other families that, in conjunction 

 with their peculiar outline and mode of flight, they can 

 usually be recognised at a glance. Other distinctive features 

 are, that their colours are always nearly the same on the 

 under surface of their wings as on the upper ; they never try 

 to conceal themselves, but rest on the upper surfaces of 

 leaves or flowers ; and, lastly, they all have juices which 

 exhale a powerful scent, so that when one kills them by 

 pinching the body, the licjuid that exudes stains the fingers 

 yellow, and leaves an odour that can only be removed by 

 repeated washings. 



Now, there is much direct evidence to show that this 

 odour, though not very offensive to us, is so to most insect- 

 eating creatures. Mr. Bates observed that, when set out to 

 dry, specimens of Heliconidae were less subject to the attacks 

 of vermin ; while both he and I noticed that they were not 

 attacked by insect-eating birds or dragonflies, and that their 

 wings Avere not found in the forest paths among the numerous 

 wings of other butterflies whose bodies had been devoured. 

 Mr. Belt once observed a pair of birds capturing insects for 



