1 893.] ENTOMOLOGICAL NEWS. 71 



slope, being that region west of the Continental divide in both 

 Americas, is T. pennipes; or, in South America, what I have 

 considered as its Chilian representative, T. arcuata. The genus, 

 therefore, seems to attain its most perfect development on the 

 Atlantic coast. It is notable, also, that it is a genus that is not 

 represented in Europe, but is strictly American. It is quite pos- 

 sible that these facts have an important bearing on the subject of 

 the phenomena of life on the Pacific coast, treated in such an 

 interesting manner by Dr. S. H. Scudder in the "Overland 

 Monthly" for April, 1892.* Dr. Scudder shows, in this article, 

 that those butterflies and other insects, which are common to 

 eastern and western America and Europe, have the greatest num- 

 ber of broods annually in the eastern United States, while in the 

 same latitudes in Europe and on the Pacific coast they have a less 

 number. In the same manner, genera common to those three 

 regions exhibit a greater number of species on the Pacific slope 

 and in Europe than in the eastern United States. Trichopoda 

 does not tend to confirm this law, since it reaches its greatest de- 

 velopment on the Atlantic coast, at least in number of species. 

 Does the fact that the genus is peculiarly American have any 

 bearing on this point ? Does a genus that is peculiar to America 

 naturally reach its highest development on the Atlantic coast ? 

 The study of the single species, T. pennipes, may give a different 

 result. 



Either the natural conditions prevailing west of the backbone 

 of the continent, which restrain the tendency to the over expen- 

 diture of vital energy, have worked to the disadvantage of other 

 species of the genus, which have not been able to adapt them- 

 selves thereto; or, what is somewhat more probable, these species 

 originated in the eastern region and have never passed the bar- 

 rier of altitude which lies between them and the Pacific coast. 



It should be noted, also, in this connection, that the genus 

 Trichopoda probably represents the most highly specialized type 

 of insects. 



LORD WALSINGHAM has accepted the vacant position on the editorial 

 staff of "The Entomologist's Monthly Magazine," caused by the death 

 of Mr. H. T. Stainton. 



* The " Californian" of the future "Overland Monthly," April, 1892, pp. 383-386. 



