the Excrement of Insects. 25 



liibited, under tlie microscope, spherical granules, as of lithate of 

 ammonia, globules like those of starch, and which were colored 

 blue by tincture of iodine, and irregular fragments as of vegetable 

 matter. The presence of lithic acid was detected by the usual 

 test. It was tested for urea; but the presence of this substance 

 was not demonstrated, which may have been owing to the small- 

 ness of the quantity subjected to experiment. 



27. A cock-roach just killed, taken from the apothecary's store 

 room, was found, on being opened, to have its stomach and intes- 

 tine distended with small dark fragments, amongst which were 

 some possessing the color and lustre of Spanish flies. A system 

 of tubes, containing a white opaque matter, was seen on each side, 

 and at right angles to the intestine. This matter examined was 

 found to contain lithic acid, and was probably in combination with 

 ammonia. 



28. A large dragon-fly, in confinement, voided pretty much 

 reddish excrement, which, under the microscope, appeared in little 

 aggregate masses, with (when broken down and diffused in water) 

 some very thin colorless and transparent hexagonal plates. It 

 dissolved in part in nitric acid, and heated acquired a rich purple 

 color. 



29. Another dragon-fly, a smaller species, voided in confine- 

 ment several small cylindrical masses, in part brick-red, and in 

 part blackish. Broken and mixed with water, under the microscope 

 they appeared to be composed of the debris of insects, portions 

 of wings, legs, tic, and of granules. Acted on by dilute nitric 

 acid, a partial solution was immediately effected, in which lithic 

 acid was clearly detected by the ordinary test. 



30. A large Mantis (il/. Siccifolia? Linn.), in confinement, 

 voided a good deal of excrement in small pellets, some blackish, 

 some brown. The latter, under the microscope, after admixture 

 with water, showed numerous granules larger than those of lithate 

 of ammonia commonly are, being about t>-q^-q of an inch in 

 diameter, yet having the properties of this compound, as tested 

 in the ordinary way. 



31. A large humble-bee, its prevailing color black, in confine- 

 ment voided pretty much excrement in a semifluid state. Un- 

 der the microscope it appeared to consist chiefly of corpuscles, 

 reminding one of the pollen of flowers. Acted on by dilute 

 nitric acid and heat, the presence of a little lithic acid was demon- 

 strated. 



32. Several wasps, together with their comb, placed under a 

 glass shade, were found dead on the fourth day of their confine- 



