XXVi INTRODUCTION. 
during a four years’ residence in Guatemala and the Colombian State of Panama, 
Smaller collections have been made by Messrs. Forrer, Buchan-Hepburn, and Becker 
in Northern Mexico, by Mr. and Mrs. H. H. Smith in the Mexican States of Guerrero, 
Vera Cruz, and Tabasco, by Mr. Gaumer in Yucatan, by Mr. J. Flohr in various parts of 
Mexico, by Mr. Conradt in Guatemala, by Messrs. Belt and Janson in Nicaragua, 
by Messrs. Rogers and Van Patten in Costa Rica, and by Herr E. Trotsch in the State 
of Panama: all these contributing more or less to our knowledge of the fauna under 
investigation. As regards the Mexican species, we are particularly indebted to 
Mr. Flohr, who, from time to time, up to the moment of going to press, has sent us 
specimens of all the more interesting Mexican Heteromera he has been able to obtain. 
I may here state that the collection of Mr. F. Bates, by far the best collection of 
Heteromera in existence, has been of the greatest assistance to me throughout, it being 
especially rich in American forms. Dr, Horn, ever ready to help, has been kind 
enough to communicate authentically named examples of very many North-American 
species for comparison, and also to send us specimens of various North-Mexican forms ; 
and in concluding these remarks I have to tender him my grateful acknowledgments. 
G. C, ©. 
March 18938. 
