446 Professor Williston on the Diptera of St. Vincent. 



the southernmost portions of the United States, especially 

 Florida, whose fauna seems to partake largely of the 

 southern type. 



It may, perhaps, occasion some surprise that so large a 

 proportion of the foregoing species are determined as new. 

 This is due to two facts. First, the larger portion of 

 the species of the collection are small or very small, the 

 majority not exceeding four millimetres in length and 

 nearly a half requiring the use of a compound microscope 

 for their study. Second, the small, obscure species 

 are exceedingly difficult to recognize from the majority of 

 the existing descriptions of South American forms. I can- 

 not hope to have avoided all synonyms. That some of the 

 species have been previously described from South and 

 Central America will be a matter of comparative indiffer- 

 ence if I have succeeded in so describing and figuring the 

 present ones that the future observer of specimens from 

 these regions will be able to determine them with tolerable 

 certainty. 



My thanks are due to Professor Aldrich for so kindly 

 undertaking the study of the families Dolichopodidse and 

 Phoridee, to which he has given so much attention in 

 recent years. 



Explanation op Plates YIII., IX., X., XI., XII., 

 XIII., & XIV. 



Plate VIII. — See explanation facing Plate VIII. 

 Plate IX „ Plate IX. 



Plate X. 

 Plate XI. 

 Plate XII. 

 Plate XIII. 

 Plate XIV. 



Plate X. 

 Plate XI. 

 Plate XII. 

 Plate XIII. 

 Plate XIV. 



