PROTECTIVE MIMICRY. 251 



time. The pairing and egg-laying takes a very short time, 

 even among those insects which do not lay all their eggs at 

 once ; the risk run by the insect before it has accomplished its 

 purpose is therefore very slight, compared with the dangers 

 incurred by a caterpillar, which has sometimes two seasons 

 to pass through in preparation for the chrysalis stage, and is 

 constantly exposed all this time to numerous enemies, belonging 

 to almost every group of the animal kingdom. This is perhaps a 

 reason why we see such numerous and varied devices, whereby 

 caterpillars delude, warn, or frighten their enemies ; and it 

 is perhaps also a reason which explains the great dearth of 

 such devices among butterflies and — though apparently to a 

 less extent — among moths. It is therefore surprising to find 

 so many examples of apparently useful mimicry among butter- 

 flies. It has already been pointed out that protective colora- 

 tion is not very useful in these insects ; warning coloration 

 and mimicry are therefore the only colour modifications of a 

 protective value which they could advantageously assume ; 

 and, it must be admitted, it is precisely these modifications 

 which are met with. 



Summary. 



All these facts, which are of course only a selection from 

 more numerous instances that might be brought together, 

 show ' that very close superficial resemblances frequently exist 

 between animals more or less remotely allied. These resem- 

 blances may be in form (c.//., snake and blindworm), or colour 

 {e.g., various Lepidoptera), or form and colour combined {e.g., 

 Leptalis and Heliconidfe). Eesemblauces between animals of 

 widely diff'erent groups (e.g., caterpillar and shrew) are so 

 very rare as to be probably regarded as purely accidental ; 

 resemblances between more nearly allied forms (<'.y., Lepido- 



