212 SOCIAL LIFE IN THE INSECT WORLD 



males, perceiving no odour, did not arrive so long as 

 that condition of things obtained. It was plain that 

 this failure of transmission was not due to the action 

 of the glass as a screen simply, for if I established a 

 free communication between the interior of the bell- 

 glass and the open air by supporting it on three small 

 blocks, the moths did not collect round it at once, 

 although there were plenty in the room ; but in the 

 course of half an hour or so the feminine alembic 

 began to operate, and the visitors crowded round the 

 bell-glass as usual. 



In possession of these data and this unexpected 

 enlightenment I varied the experiments, but all pointed 

 to the same conclusion. In the morning I established 

 the female under the usual wire-gauze cover. For sup- 

 port I gave her a little twig of oak as before. There, 

 motionless as if dead, she crouched for hours, half 

 buried in the dry leaves, which would thus become 

 impregnated with her emanations. 



When the hour of the daily visits drew near I removed 

 the twig, which was by then thoroughly saturated with 

 the emanations, and laid it on a chair not far from the 

 open window. On the other hand I left the female 

 under the cover, plainly exposed on the table in the 

 middle of the room. 



The moths arrived as usual : first one, then two, then 

 three, and presently five and six. They entered, flew out 

 again, re-entered, mounted, descended, came and went, 

 always in the neighbourhood of the window, not far 

 from which was the chair on which the twig lay. None 

 made for the large table, on which, a few steps further 

 irora the window, the female awaited them in the wire- 



