the Excrement of Insects. 23 



a good deal of excrement in confinement, some portions of which 

 were whitish, some reddish. In the former, under the micro- 

 scope, a few crystals were seen, as of lithic acid, and numerous 

 granules, about -^^q-q of an inch in diameter, as if of lithate of 

 ammonia. The latter contained no crystals, only granules. 

 Heated with nitric acid, lithic acid was strongly indicated in 

 both. 



17. A brown moth, of a lighter color than the preceding, of 

 about the same size, voided a pretty copious fawn-colored excre- 

 ment, which, mixed with water, under the microscope exhibited 

 aggregated masses as if formed of granules, and some crystals, 

 square plates, and one low four-sided prism. The granulated 

 masses and crystals dissolved in nitric acid, and the rich color, 

 the mark of lithic acid, was produced by exposure to a regulated 

 heat. 



18. A dark brown moth, of medium size, in confinement during 

 twenty-four hours, voided a good deal of reddish excrement, 

 partly in minute granules, and partly in little masses, probably 

 aggregates of the granules ; such they appeared under the micro- 

 scope. No crystals were seen. By the nitric acid and heat test, 

 lithic acid was found to abound. Twenty-four hours longer in 

 confinement this moth was found dead, after having voided a good 

 deal more of red excrement, like the preceding, excepting that in 

 one small portion of it crystals of lithic acid (hexagonal and qua- 

 drangular plates) were observable. The nitric acid test gave the 

 same result as the last. 



19. A small white moth, that died after being confined twenty- 

 four hours, voided a pretty considerable quantity of semifluid, 

 almost colorless excrement, composed chiefly of granules, which, 

 from the action of nitric acid, it may be interred were of lithate 

 of ammonia. 



20. A small grey moth voided a minute portion of brownish 

 excrement, consisting, as seen under the microscope, of little 

 granular masses, and dispersed granules without crystals : from 

 the effect of nitric acid and heat it would appear that they were 

 composed principally of lithate of ammonia. 



21. A brown moth, about half an inch in length, in confinement, 

 before it died voided a portion of excrement so minute in quantity 

 that it was not easy to collect; notwithstanding, it afforded satis- 

 factory proof of the presence of lithic acid by the nitric acid test. 

 The rich distinctive hue was visible to the naked eye, and well 

 shown under the microscope. 



22. A delicate white moth, with a tufted tail, deposited in con- 



