MIMICRY AND LIFE-HISTORY 243 



8. Conditions of a Species in any locality are chiefly 

 determined by its Habits and Life-history. 



In the last Section it was shown that there is no uni- 

 formity in the effects produced in any locality. In this 

 Section it will be made clear that there is no uniformity 

 in the forces which, by their uniformity, are supposed to 

 produce the effects. When we are told that common 

 food, common climate, &c, produce a common effect, we 

 have the means for proof or disproof in, at any rate, some 

 striking examples ; for we know the food and conditions 

 of certain species which exhibit mimetic or common warn- 

 ing associations. There are many examples of Longicorn 

 beetles mimicking Lycidae (Malacoderm beetles) in the 

 same locality ; but during the earlier stages, in which the 

 appearance of the final stage is determined, the former 

 lives in a burrow, feeding upon wood or the tissue of 

 plant-stems, and sheltered from many of the climatic 

 influences and changes, while the other lives in the open, 

 freely exposed to them all, and sustained by an exclusively 

 carnivorous diet. I owe this suggestive comparison and 

 the Section which arose out of it to a conversation with 

 Mr. C. J. Gahan, of the British Museum. Similarly in 

 the case of South-American moths belonging to the 

 Castniidae, which resemble Ithomiine butterflies (see 

 Section 12, page 261), the larvae of the former burrow in 

 plants, while the latter are freely exposed on the leaves 

 which form their food. 



It is hardly necessary to insist on the importance of the 

 larval stages in this respect. When the imago emerges 

 from the pupa and its expanded wings have dried, it has 

 assumed its permanent appearance, and nothing that it 

 will eat or endure henceforward, produces any further 

 effect upon its colours or patterns, &c. Hence identity 

 of food and conditions during the final stage cannot be 

 of any assistance in the interpretation of Mimicry. It is 

 necessary to point this out clearly, inasmuch as Beddard 

 has said, speaking of the resemblance between Eristalis, 

 the drone-fly, and the hive-bee, ' It is an interesting fact, 

 in connection with the resemblance between this fly and 



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