14 ENTOMOLOGICAL SOCIETY 
Mr. Mann commented on the extensiveness and variety of the 
literature of science as a whole, and the impossibility of obtain- 
ing a knowledge of the literature relating to special departments 
of research without the aid of summaries or indices prepared for 
the purpose. He then dwelt upon the multitude of separate 
partial indices now in existence, upon the difficulties experienced 
in making use of these indices, and the waste of labor expended 
in disconnected attempts to obviate these difficulties. He ad- 
verted to the advantage which would accrue to all students 
through co-operative effort to obviate the difficulties described, 
and remarked upon the necessity, in case such co-operation is to 
take place, of determining upon a system of carrying it out. He 
concluded with remarks on the appropriateness of the execution 
of a plan of co-operation in connection with the work of the 
Division of Entomology in the U. S. Department of Agriculture. 
Mr. Schwarz read a paper on the changes that take place in 
the imago state of Coleoptera. After briefly referring to the 
changes brought about by the inclemency of the weather, old 
age and other external influences, he explained the general differ- 
ences between the immature and mature imago, and more par- 
ticularly such differences of a more structural character. These 
are the loss of the front tarsi in certain coprophagous Scarabaeidaa 
and the loss of the mandibular appendages in the family 
OtiorhynchidaB. As a third instance of such changes Mr. 
Schwarz exhibited immature specimens of Mezium americanum, 
which are all covered with rows of very conspicuous clavate 
bristles, whereas in the mature specimens these bristles are so 
completely lost on the elytra that even their points of insertion 
cannot longer be observed. 
A discussion on the habits of Mezium followed. Dr. Riley 
stated that he had found it in old hay. Mr. Hubbard mentioned 
finding it in immense numbers in a rat's nest, and Mr. Pergande 
stated that he had commonly bred the allied Ptinus brunneus 
from rat's dung. 
Dr. Riley made some remarks on the collection of insects 
made at Point Barrow, Alaska, by Prof. John Murdoch,* calling 
attention to the fact that, as with other collections from arctic re- 
gions, a large percentage of the species was common to both 
Vide p. 9. 
