the Excrement of Insects. 2l 



by the crystals obtained on evaporation after the addition of mu- 

 riatic acid. On this addition being made, a smell was perceived 

 like that from the urine of the horse. The Sphinx shortly after, 

 and before it had taken any food, was killed and examined ; its 

 stomach and intestine were found empty. 



9. A Sphinx from larva, No. 3, less than a month in under- 

 going its metamorphosis, voided, on leaving its puparium, a good 

 deal of turbid, reddish-brown fluid, which, subjected to examina- 

 tion, was found to contain lithate of ammonia, a trace of the pur- 

 puraie of ammonia and of hippuric acid. Under gentle pressure, 

 when laid hold of, this Sphinx discharged pretty much semifluid 

 matter of a brick red color, which, under the microscope, was 

 found to be composed of spherical granules, varying in diameter 

 from -j-aiuo '° Tsh'Uo °^ ^^ inch. After standing a little while 

 many of them coalesced and formed larger granules. Tested by 

 nitric acid and a regulated heat, they had the character of lithate 

 of ammonia. I may mention further, that in the forsaken puparium 

 there was a good deal of whitish matter ; this washed out with water 

 and collected, under the microscope was seen to consist of granules 

 of about -j-^^^^ of an inch in diameter; and tested, was found 

 likewise to be of lithate of ammonia. The quantity of excrement 

 accumulated in this moth during its change of state, and voided 

 on acquiring its perfect form, was truly surprising, and not less so 

 the abundance in it of lithate of ammonia. 



I shall now pass to the results obtained from insects caught, 

 and consequently of uncertain age in relation to their last birth 

 or time of quitting their puparia. 



10. A Sphinx, after about twenty-four hours' confinement, under 

 glass, with a free supply of air, died without yielding any excre- 

 ment. On opening it the lower portion of its intestine was found 

 distended with a brownish opaque fluid. The opaque matter, it 

 may be inferred, was lithate of ammonia; for under the micro- 

 scope it exhibited the finely granular condition of this compound, 

 and when acted on by dilute nitric acid and heat, was first dis- 

 solved, and then acquired the rich purple color distinctive of lithic 

 acid. 



On examining the abdomen, opening the Sphinx under water, 

 some minute cells, with delicate tubes proceeding from them — 

 part I believe of the renal apparatus — were observable by means 

 of the microscope; they contained an opaque matter, probably 

 lithate of ammonia, for, tested for lithic acid, proof was obtained 

 of its presence. 



Whilst in Barbados other large moths of the Sphinx tribe were 



