16 SCHMIDT ON THE COMPARATIVE PHYSIOr.OGY 



which held the substances sohible in water. The recently pre- 

 pared ash does not however effervesce with acids ; it contains 

 soda and phosphoric acid, as proved by the yellow precipitate 

 with salts of silver. The alkaline reaction is thus understood, 

 and the effervescence observed by Odier is explained by the 

 easy decomposition of the tribasic phosphates. The substances 

 soluble in potash consist of the proteine of the above-men- 

 tioned muscles and a brown resinous matter which unites the 

 fibrous tissue. 



So much for the illustration of the historical points. I shall 

 now proceed to my own observations. 



At first I made use of the Cockchafer ; the histological ele- 

 ments of the tegument and elytra are the same, it is however 

 difficult to decide positively as to this point before having re- 

 course to the potash ; we find several superimposed fibrous mem- 

 branes, which become distinct on disintegration ; their upper 

 surface, which is especially impregnated with the resinous brown 

 colouring matter, and covered with a thin epithelium consisting 

 of six-sided cells, exhibits cylindrical depressions placed at regu- 

 lar distances, from which simple elongated cells, " hairs," arise. 



A portion of the elytrum was exhausted successively with 

 water, alcohol and aether, and lastly with a tolerably concentrated 

 solution of potash with heat, until it appeared colourless and 

 transparent; during the last operation a little ammonia was 

 evolved, evidently from a small portion of the muscles of the 

 wings remaining. I examined it microscopically ; the epithe- 

 lium, hairs and their cylindrical depressions were unaltered, the 

 brown resinous substance had disappeared ; several layers of 

 sharply defined muscular fibres were perceived superimposed in 

 such a manner, that a layer of transverse fibres was placed over 

 each layer of longitudinal ones, and so on, so that the whole, 

 with the hair-cells which remained unaltered in the uppermost 

 layers, presented the appearance of a regular and elegant trellis- 

 W'ork. H. Meyer* has fully described this structure in Lucanus 

 cervus ; his illustration applies to MeloloiUha and the elytra of 

 most of the beetles, so that I consider further description of their 

 form (which is very uninteresting without the history of develop- 

 ment) as superfluous. 



The brown colouring matter with which the fibrous layers are 

 impregnated and by which they are united, is precipitable from 

 * Mullei's Arclnv. 1842, p. 12-16. 



