112 CANKEB-WOEM. 



The moths congregrated in such numbers, one upon another, that at 

 some points they were nearly or quite upon a level with the outer band, 

 and the outside ones passed on to it. Upon reaching its upper edge, 

 if the rope filling were on a level with it, they would pass over on to 

 the tree above ; but if the rope happened to be below the top of the 

 bands, the insects would not attempt to crawl down so as to reach the 

 rope, but would go round the edge till they came to a place where it 

 was up to tbe level and then pass over. This suggested the idea that 

 if the upper edge of the tin band were made to stand out free all 

 around, the insects would probably be completely baulked in their as- 

 cending instincts. As the free upper edge of the outer band was the 

 essential part of this experiment, I simplified the operation by omitting 

 the inner band, and putting a single tin band outside of the rope band 

 and placing it so that the rope should be about midway between its 

 upper and lower edges. This simple contrivance seemed to be success- 

 ful for all practical purposes. Comparatively few moths got on to the 

 outside of the band, and these, upon arriving at its upper edge, and 

 being unable to go higher, kept traveling round and round the edge 

 until they became discouraged. 



This simple method of placing a single tin band over a band of rope 

 was adopted on the 15th of March, and though the moths continued to 

 run in diminishing numbers all through the remainder of the month, 

 yet only a single moth is recorded in my diary as having been seen 

 above the band after this date. 



The next practical question that arises is : what course will these 

 egg-laden moths take if prevented from ascending the tree above a cer- 

 tain circle. My observations show that they will not return and de- 

 posit their eggs amongst the dead grass and leaves around the foot of 

 the tree, as I had apprehended, nor even upon the lowermost part of 

 the trunk ; but that, faithful to their instinct, they will deposit their eggs 

 as high up as they can get. Accordingly, I found the under side of 

 the rope densely sprinkled with eggs, and the bark of the tree, for sev- 

 eral inches below, almost covered by them, in many places piled upon 

 each other. If there be loose scales of bark at hand, they will crowd 

 the spaces beneath them with eggs, and when these fail they will 

 adopt the only alternative the emergency admits of, and lay their eggs 

 upon the exposed surface, though at the time they are deposited the 

 crowded bodies of their companions must furnish a temporary shelter. 



If the simple apparatus above described proves as effectual, upon 

 further trial, as it has in my experiments, and if the intercepted moths 



