Wanted — Literature and determined specimens of Collem- 

 bola, in exchange for local forms and literature. G. Bacon, 

 Claremont, Cal. 



Wanted — Determined specimens of Thysanura in exchange 

 for local species. E. Gardner, Claremont, Cal. 



Wanted — Separates relating to the nervous system and sense 

 organs of the invertebrates in exchange for reprints by a number 

 of authors on this and other topics relating to the anatomy of 

 invertebrate animals. W. A. Hilton, Claremont, Cal. 



Tabanidfe from all parts of North America to exchange for 

 Tabanidae from the Western United States and Mexico and 

 Central America. Jas. G. Hine, Ohio State University, Colum- 

 bus, Ohio. 



