AMERICAN DIPTERA. 141 



Zoology, together with 11.3% additional species of other 

 authors recognized by these gentlemen, we can judge how 

 valuable a service Osten Sacken rendered American dipter- 

 ologists in securing the return to this country of the material 

 he sent to Loew for study. Of the genera for the same time 

 and territory, 72.4% were erected by Loew, and 27.6% by 

 Meigen, Wiedemann, Macquart, Jaennicke, and Phillipi. 



Of American writers Dr. Williston stands forth as the first 

 to do thorough systematic work upon the Asilids, and his 

 publications in the Transactions of the American Entomo- 

 logical Society and in his Manual, are of great value, and 

 have been very useful in the preparation of this paper. The 

 work of Mr. D. W. Coquillett and Prof. C. W. Johnson, while 

 given more to description of new forms, is indispensable. 

 These three gentlemen have added nearly sixty new species 

 and five new genera; of the latter, three are those of Dr. 

 Williston, and one each of Mr. Coquillett and Prof. Johnson. 



COLLECTIONS. 



The best collection of Leptogastrinae and Dasypogoninse is 

 the type collection of Loew and Osten Sacken now at the 

 Museum of Comparative Zoology of Harvard University. 

 The specimens, with few exceptions, are in good condition. 

 The collections of the National Museum and of the American 

 Entomological Society of Philadelphia are very good and 

 growing, while those of the American Museum and Brooklyn 

 Institute, though at present less in extent, contain valuable 

 material. The collection of the Massachusetts Agricultural 

 College contains several types, homotypes, and metatypes. 

 The writer has never had the privilege of seeing the collection 

 of the University of Kansas, but as this contains all the ma- 

 terial worked on by Dr. Williston, together with his numerous 

 types, it cannot fail to be most valuable. Of private collec- 

 tions, that of Prof. C. W. Johnson, Curator of the Boston 

 Society of Natural History, is very good, and for systematic 

 study takes a very high rank. Besides these, the collections 

 of the New York State Museum, and of the Colorado and 

 North Carolina Experiment Station, are worthy of mention. 



TRANS. AM. ENT. SOC, XXXV. APRIL, 1909. 



