THE DIGGER WASPS OF NORTH AMERICA OF THE GENUS 

 PODALONIA (PSAMMOPHILA) 



By H. T. Fernald, 



Of the Massachusetts Agricultural Experiment Station, Amherst 



INTRODUCTION 



The studies presented in this paper were begun a number of years 

 ago and have been continued in the intervals between the other 

 duties of the writer. That they were not completed earlier is due, 

 first, to those duties; and second, to the great amount of variation 

 present in the insects concerned. This variation has made necessary 

 the examination, over and over, of thousands of specimens and their 

 study in relation to the climatic conditions of the localities where 

 they were captured, which has required much time. 



This paper has been based on the remarkably fine collection of 

 the genus in the United States National Museum, supplemented by 

 loans from more than 50 other museums and private collections. 

 During nearly six months spent in Europe for the purpose, the types 

 there were carefully studied and compared with material taken from 

 this country, and almost every type of the North American species, 

 both in Podalonia and in SpJiex {Ammophila Authors), which is still 

 in existence there, was found and examined. 



This paper deals with the relatively small genus Podalonia Spinola; 

 a second on the much larger genus Sphex is well along, and it is the 

 hope of the writer that it will soon be ready for publication. 



To all those who loaned specimens for study and who have so 

 patiently waited year after year for their return, the writer desires 

 to express his grateful appreciation; to name them would take an 

 unwarranted amount of space. But he desires to express his thanks 

 in particular to the officers of the United States National Museum; 

 of the American Entomological Society, and of the Museum of Com- 

 parative Zoology of Harvard University for the opportunities given 

 him to examine the types of species belonging to the group, in those 

 collections; and to S. A. Rohwer, of the United States Bureau of 

 Entomology, for his constant cooperation, his kind suggestions, and 

 the aid received from the free statement of his views on points which 

 have seemed debatable. 



No. 2681.— Proceedings U. S. National Museum. Vol. 71. Art 9. 



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