Miscellaneous. 231 



variability, not only between the divisions of a tribe, but sometimes 

 even between the representatives of the same genus. The different 

 species of Cockchafers and Cetonice furnish curious examples of this 

 fact, which is still more striking in the Anomalce. It is only between 

 the most nearly allied species that we meet with a nearly complete 

 similarity in the form of the organ of intromission. It would appear 

 that Nature has taken the most minute care to prevent the mixture 

 of types, and that crossing is practicable only within very restricted 

 limits. 



The female organs consist normally of two identical ovaries, formed 

 of a number of sheaths corresponding exactly in each individual with 

 that of the testicular capsules. These sheaths are united with each 

 other and supported by a suspensory cord. There is also a more or 

 less developed copulatory sac and some accessory glands. 



The Coprince, from which the Aphodii must be separated, present 

 a very remarkable character, namely, the occurrence, well known in 

 Birds, of the abortion of the ovaries of the right side. That which 

 exists, even, is reduced to a single sheath of considerable length. At 

 its base there are several small vesicular appendages, the vestiges of 

 the aborted sheaths. 



In the Geotrupince there is no apparent copulatory sac. The 

 reservoirs destined to contain the seminal fluid of the male, which 

 indeed are very small, are concealed beneath the muscular envelope 

 of the base of the oviduct. In the Cetonince the sheaths are very 

 short, and, as a consequence of this modification, the suspensory 

 cord disappears. 



In the GlapTiyrincBy Melolonthince, Rutelince, and Scarabceince 

 neither the male nor the female generative organs present any marked 

 differences. 



From his investigations the author draws the following conclu- 

 sions : 



1 . There is always an almost exact similarity between the very 

 nearly allied species of the same genus. This furnishes evidence in 

 support of the happy definition of a genus given by M. Flourens. 



2. Between two genera there are important modifications well 

 adapted to characterize them. 



3. These modifications, becoming more considerable in the repre- 

 sentatives of higher groups, such as tribes, furnish valuable indica- 

 tions for zoologists. 



4. The differences observed between i}\eGlaphyrince,Melolonthince, 

 Rutilince, and Scarabceince, which are admitted as tribes, are not 

 comparable in value to those which distinguish the Cetonince, and 

 still less to those which separate the Geotrupince and Coprince. 



5. In the case of types of which the natural relations could not 

 be appreciated with certainty by the consideration either of the ex- 

 ternal characters or of certain internal organs, the knowledge of the 

 generative apparatus allows their position to be more accurately de- 

 termined. Of this the comparison of the Arthrophagi and Aphodii 

 furnishes a striking example. Comptes Rendus, January 16, 1860, 

 p. 158. 



