28 Dr. John Davy's Observations on 



species having been determined by Francis Walker, Esq., and by 

 J. W. Douglas, Esq., who, at your request, were so obliging as 

 to examine them. 



39. A butterfly {Vanessa Uriicce), on pressure being applied to 

 its abdomen when in a torpid state (it had been caught on the 

 wing), a comparatively large quantity of semifluid excrement was 

 ejected, of a rose color, as if from the presence of rosacic acid. 

 Under the microscope it was seen to be very uniformly composed 

 of spherical granules, of about -j^gljo^ of an inch in diameter. It 

 dissolved innnediately in nitric acid, and when evaporated and 

 heated, acquired the rich purple hue indicative of lithic acid, or 

 of lithate of ammonia. 



40. Another butterfly, of the same kind, voided in confinement 

 a small quantity of reddish excrement ; in which, besides granules, 

 as of lithate of ammonia, rhomboidal plates, more or less trun- 

 cated at their angles, probably of lithic acid, were seen under the 

 microscope. The granules dissolved rapidly in dilute nitric acid ; 

 the crystals slowly. The whole when evaporated and heated ac- 

 quired the color indicative of lithic acid. 



41. A Vanessa lo, in confinement, voided some greyish excre- 

 ment, which under the microscope, and the action of nitric acid 

 and heat, was found similar to the first of the two preceding 

 instances. 



42. A moth (Smerinthus Popid'i), in confinement, voided pretty 

 much reddish excrement, which was found to consist principally 

 of lithate of ammonia. 



43. Another moth {Cramhus culmellus), pressure being applied 

 to its abdomen, a minute quantity of light colored excrement was 

 discharged, which, on examination, proved similar to that last 

 mentioned. 



44. A moth ( Triphcena pronuba), in confinement, voided a good 

 deal of fawn-colored excrement. Under the microscope, it ex- 

 hibited spherical granules, as of lithate of ammonia, with which 

 were intermixed low four-sided prisms or cubes of a pretty large 

 size. Acted on by nitric acid and heat, the rich purple, marking 

 lithic acid, was produced. 



45. Another moth of the same kind as the last, in confinement, 

 during one night voided excrement in three separate portions ; 

 one reddish, one brown, one of a fawn color. They were found 

 to consist principally of litliate of ammonia. On pressing the 

 abdomen of this moth, a reddish brown fluid was obtained, which 

 had the smell of human urine, and which was changed to a honey 

 smell on the addition of a little nitric acid. On slow evaporation 



