424 Extract from Note Book regarding the Genus Paussus. [No. 138. 



the same description, which is attached to the upper exterior margin 

 of the abdomen, and which by the aid of a pin's point may be lifted up, 

 and in a slight degree outspread, but collapsing immediately the im- 

 pediment is removed. It would be difficult to assign reasons for the 

 different addenda in the form of these insects, and observation alone 

 can afford a clue to their uses, but that they are objects of extreme 

 utility, and perhaps absolutely necessary in their economy as is easily to 

 be conceived. Possibly the last mentioned appendages may be a 

 source of further protection granted these curious insects, which are 

 brought into play as danger may threaten ; for in one I captured on the 

 night of the 30th ultimo, and which flew into the lights on the table, 

 I observed that when placed under the microscope, if these papillae 

 were touched, that they possessed the power of discharging a yellowish 

 milky liquid, resembling pus in consistency, and which speedily over- 

 spread the lower part of the elytron, granulating into small egg- 

 shaped grains. On repeating the irritation the same results occurred, 

 and in order to be certain of the fact, I tried each elytron twice with 

 the same effect. In my first trial the emission was so sudden and took 

 me so much by surprise, that viewing the insect through the medium 

 of the microscope, I fancied it sufficiently near to be injurious, and 

 incontinently let it fall. I should mention, that in all these trials, each 

 emission was accompanied with a faint acidulous odour. Although the 

 appearance of each discharge obtained on the elytron, I am inclined 

 to believe, that properly speaking, it issued from the foliaceous appen- 

 dage on the abdomen, and that it spread over the wing case in con- 

 sequence of the peculiar shape of the shards at the part which over- 

 laps the extremity of the above-mentioned organ, but my experiments 

 were unfortunately closed, ere I could satisfy my doubts, as my servant 

 in removing the microscope to another table contrived to lose my spe- 

 cimen ; since which I have been unsuccessful in making a recapture. 

 At one time previous to my loss, I was inclined to believe that a mi- 

 nute perforation existed in the exterior angle of each elytron, with 

 margins sufficiently elastic to allow the liquid to pass through, closing 

 immediately after the emission, but I could not bring myself to any 

 certainty on this point. 



After capture, the Paussus may be made to lose its powers of crepi- 

 tation by too much irritation, at which time it will resort to a very 



