576 ' PHILOSOPHICAL TRANSACTIONS. [aNNO I7OI. 



Sanctorii Sanclorii de Statica Medicina A})horismornm Secliones Septem, cum 

 Commentario Martini Lyster. Lo7id. 1701, 8vo. N° 270, p. 832. 



Of this work an account has been given under the life of Sanctorius, inserted 

 in vol. ii. p. 412 of this Abridgment. 



Proposals for Printing by 'Subscription, the third and last volume of the General 

 History of Plants. By John Ray, F.R.S. In Fol. N° 270, p. 833. 



On an Insect commonly called the Death- fVatch.* By the Rev. Mr. JVm. Derham. 



N° 271, p. 832. 



Of these death-watches, or insects which make a noise like the beats of a 

 watch, I have observed two sorts. Of one of them I find a very exact account 

 in Phil. Trans. N'' 245. The insect there described being less shy, and much 

 larger than that which I discovered some years since. This year I caught many 

 of them ; two of which, a male and female, I kept alive in a little box about 3 

 weeks; and could make one of them beat whenever I pleased, by imitating his 

 beating. At last one died, and the other gnawed its way out through the side 

 of the box. 



The reason why I judge these to be male and female is, because I have often 

 by my ticking noise invited the male to get up upon the other in the way of 

 coition. That which I took to be the male was somewhat less than the other, 

 and was freest in answering my beats. Before he got upon the other, he would 

 beat very eagerly ; and when he found that he was got up in vain, he would get 

 off" and beat again eagerly, and then up again. From whence I guess these 

 pulsations to be the way whereby these insects woo each other, and invite to 

 copulation. This Mr. Allen takes no notice of in his account, from which I 

 differ only concerning the part with which the ticking noise is made, which he 

 says is " the extreme edge of the face, which may be called the upper lip ;" 

 but I observed the insect always to draw back its mouth and beat with its 

 forehead. 



The other death-watch is in appearance quite different from the last ; it beats 

 only about 7 or 8 strokes at a time, and (juicker; but this will beat some hours 

 totiether without intermission, and his strokes are slower, and like the beats of 

 a watch. I have several years observed these two sorts of beating, but took it 

 to be made by one and the same animal. The insect which makes this long 



* See note relative to this insect at p. 319 of this Ith vol. of the Abridgment. 



