Capt. Boyes on the (Economy of the Paussidse. 89 



What should bring these insects in nearer conjunction with the 

 genus Carahus is the curious fact, that on being seized they emit 

 from the anus a very acrid liquid, accompanied by an explosion and 

 attended with a strong scent resembling that produced by Brachini and 

 other allied genera when similarly treated, and although in minuter 

 quantities, it is abundantly sufficient to produce a very sensible heat, 

 and the crepitation may be distinctly heard and felt. On Paussus 

 Fichtelii being captured it immediately emitted two loud and very 

 distinct crepitations, accompanied with a sensation of heat and at- 

 tended by a strong acidulous scent. It left a dark-coloured stain on 

 the fingers resembling that produced by caustic, and which had a 

 strong odour something like nitric acid. A circumstance so remark- 

 able induced me to determine its truth, for which purpose I kept it 

 alive till the next morning, and in order to certify myself of the fact, 

 the following experiments were resorted to. Having prepared some 

 test-paper by colouring it with a few petals of a deep red oleander, 

 I gently turned the Paussus over it, and immediately placed my 

 finger on the insect, at which time I distinctly heard a crepitation, 

 which was repeated in a few seconds on the pressure being renewed, 

 and each discharge was accompanied by a vapour like steam which 

 was emitted to the distance of half an inch, and attended by a very 

 strong and penetrating odour of nitric acid. On removing the Paussus 

 from the paper, I found that a large spot was formed near the place 

 where the abdomen had been, and extending backwards for one-third 

 of an inch. The paper appeared strongly corroded as if with caustic, 

 the colour of the spot being light brown and totally distinct from the 

 purple of the surrounding surface. Having repeated this experi- 

 ment four times during the day with the same results, and being 

 perfectly satisfied that I could not be mistaken, I proceeded to kill 

 and set the specimen. On being thrown into boiling water the ab- 

 domen swelled up and appeared like an inflated bladder, being very 

 much distended, assuming the same appearance as that which is ob- 

 servable in Brachinus and other allied genera when they are simi- 

 larly treated, and which I have had hundreds of opportunities of ve- 

 rifying. This specimen was captured on the 17th of August, and in 

 each experiment on its detonating powers I have used a different 

 finger in giving the small degree of pressure required to induce its 

 crepitating. August 29 : all the marks off my right hand. Septem- 

 ber 3 : I have now lost all the stains on the fingers of my left hand, 

 by which it appears that those of the left hand have remained 

 eighteen days, or six days longer than those on the right. This is 

 singular enough, and I can only attribute the loss of the marks so 

 much earlier on the right-hand fingers to attrition and more constant 

 use, as the stains left were certainly much deeper in the three first 

 trials than in the latter ones, and when I used the first, second and 

 third fingers of my right hand respectively. 



Several species are provided near the exterior margin of the elytra, 

 at the posterior extremity, with a small papillaceous follicle, giving 

 cover to an elongated appendage of the same description, which is 

 attached to the upper exterior margin of the abdomen, and which 



Ann. ^ Mag, N, Hist. Fo/.xvii. H 



