THE DEATH-WATCH : NOTES AND OBSERVATIONS. 155 



That is very strange ; and very strange, too, that it should 

 usually be heard only in the autumn and winter, a most 

 exceptionable time of the year for an Anobiid beetle to begin 

 calling to "his better half part." Knowing what we do of the 

 ticking of both kinds of " death-watch," shall we not be justified 

 in assuming that the ticking Mr. Jensen-Haarup heard was not 

 that of the beetle at all, but of the book-louse, of whose ticking 

 he had probably never read. 



A. pertinax, Linn., is nearly as large a beetle as X. tessellatum, 

 Oliv., and its ticking, if any ticking be done, which I doubt, 

 should be almost as loud, and like its, not so much dependent 

 upon the weather. 



Although I had read much about the tapping of the death- 

 watch beetle X tessellatum, I had no actual experience of it 

 until last year, when for the first time I had the good fortune 

 to hear it and see it as often almost as I liked. The single 

 specimen on which my observations were made first came under 

 my notice on March 30th. It had apparently made its exit that 



Fig. 1. 



same day from a piece of an old oak stump given to me a few 

 weeks before. It continued to live for seventy-three days, and 

 during the first forty of those there was scarcely a single day 

 on which it was not possible to watch it tapping scores of times. 

 I was able to exhibit it alive and giving quite audible demon- 

 strations at a meeting of the Zoological Society in April and 

 at two meetings of the Entomological Society, one held in April 

 and the other in May, so that many naturalists had an oppor- 

 tunity to investigate the method and the conditions in which its 

 sound is produced. 



The method has frequently been described, but with a certain 

 amount of variation in the details, and in no case giving a com- 

 plete and correct idea of the insect's movements at the time it is 

 tapping. One writer says it lifts itself up on its hind legs, 

 another on its front legs, one that it hits with its jaws, another 

 with its forehead, when it " bobs its head " quickly up and down 

 against the object on which it stands. Most of them give the 

 idea that the movement is one of the head only, or of the head 

 and prothorax combined, indejDendently of the rest of the body. 



When the beetle is about to tap, it assumes an attitude 



