THE OAK EGGAR 215 



becomes a centre of attraction as active as the moth 

 herself until the effluvium is evaporated. 



Nothing visible betrays the lure. On a sheet of 

 paper, a recent resting-place, around which the visitors 

 had crowded, there was no visible trace, no moisture ; 

 the surface was as clean as before the impregnation. 



The product is elaborated slowly, and must accumulate 

 a little before it reveals its full power. Taken from her 

 couch and placed elsewhere the female loses her attract- 

 iveness for the moment and is an object of indifference ; 

 it is to the resting-place, saturated by long contact, that 

 the arrivals fly. But the female soon regains her power. 



The emission of the warning effluvium is more or less 

 delayed according to the species. The recently metamor- 

 phosed female must mature a little and her organs must 

 settle to their work. Born in the morning, the female 

 of the Great Peacock moth sometimes has visitors the 

 night of the same day ; but more often on the second 

 day, after a preparation of forty hours or so. The Oak 

 Eggar does not publish her banns of marriage before the 

 third or fourth day. 



Let us return for a moment to the problematical 

 function of the antennae. The male Oak Eggar has a 

 sumptuous pair, as has the Great Peacock or Emperor 

 Moth. Are we to regard these silky "feelers" as a kind 

 of directing compass ? — I resumed, but without attaching 

 much importance to the matter, my previous experiment 

 of amputation. None of those operated on returned. 

 Do not let us draw conclusions from that fact alone. We 

 saw in the case of the Great Peacock that more serious 

 reasons than the truncation of the antennae made return 

 as a rule impossible. 



