in PROTECTIVE EESEMBLANCES AMONG ANIMALS 51 



case with many birds, the eggs and young of which are 

 especially obnoxious to danger, and we find accordingly a 

 variety of curious contrivances to protect them. We have 

 nests carefully concealed, hung from the slender extremities 

 of grass or boughs over water, or placed in the hollow of a 

 tree with a very small opening. When these precautions are 

 successful, so many more individuals will be reared than can 

 possibly find food during the least favourable seasons, that 

 there will always be a number of weakly and inexperienced 

 young birds who will fall a prey to the enemies of the race, 

 and thus render necessary for the stronger and healthier 

 individuals no other safeguard than their strength and activity. 

 The instincts most favourable to the production and rearing 

 of offspring will in these cases be most important, and the 

 survival of the fittest will act so as to keep up and advance 

 those instincts, while other causes which tend to modify 

 colour and marking may continue their action almost un- 

 checked. 



It is perhaps in insects that we may best study the varied 

 means by which animals are defended or concealed. One of 

 the uses of the phosphorescence with which many insects are 

 furnished is probably to frighten away their enemies; for 

 Kirby and Spence state that a ground-beetle (Carabus) has 

 been observed running round and round a luminous centipede 

 as if afraid to attack it. An immense number of insects have 

 stings, and some stingless ants of the genus Polyrachis are 

 armed with strong and sharp spines on the back, which must 

 render them unpalatable to many of the smaller insectivorous 

 birds. Many beetles of the family Curculionidse have the 

 wing cases and other external parts so excessively hard, that 

 they cannot be pinned without first drilling a hole to receive 

 the pin, and it is probable that all such find a protection in 

 this excessive hardness. Great numbers of insects hide them- 

 selves among the petals of flowers, or in the cracks of bark 

 and timber; and finally, extensive groups and even whole 

 orders have a more or less powerful and disgusting smell and 

 taste, which they either possess permanently, or can emit at 

 pleasure. The attitudes of some insects may also protect 

 them, as the habit of turning up the tail by the harmless 

 rove-beetles (Staphylindidse) no doubt leads other animals 



