14 U. S. NATIONAL MUSEUM BULLETIN 216 



The Nearctic species of Scambus Hartig 1 



By G. Stuart Wallet 



In 1944, Townes published his reclassification of Nearctic Ichneu- 

 monidae; in it he listed the Nearctic species of Scambus with their 

 synonymy. As previous taxonomic work on the genus consists 

 largely of the descriptions of new species, which were included by 

 authors in several genera, the Townes arrangement marked an impor- 

 tant advance in the classification of the group and it has provided a 

 basis for the present comparative study. That a better knowledge of 

 the taxonomy of the Nearctic species is desirable has long been 

 recognized, and it is primarily to satisfy this need that the present 

 work was undertaken. It is hoped the following account will contrib- 

 ute toward a better understanding of the composition of the genus and 

 will provide a more satisfactory means for the identification of the 

 Nearctic species. 



The greater part of the material studied is in the Canadian National 

 Collection and the Townes collection, but a large number of specimens 

 have also been studied from various other collections. I have also 

 studied the types in the collections at Cambridge, New Haven, 

 Quebec, Urbana, and Washington. Where I have not personally 

 examined types I have relied mainly on material in the Townes 

 collection compared with types, and on additional information pro- 

 vided by Dr. Townes and others as noted below. 



To all who have aided in this study by the loan of material or the 

 provision of information I am very grateful. I am especially indebted 

 to Dr. Townes for information on certain genotype material and other 

 types in several European museums, and for his aid in the solution of 

 some taxonomic problems that have arisen in the course of this work. 

 Miss L. M. Walkley has supplied information on several types at 

 Washington; comparisons with notes on types at Philadelphia and 

 Washington were made for me by my associate Dr. W. R. M. Mason; 

 and Mr. J. F. Perkins of the British Museum (Natural History) has 

 been most helpful in comparing Nearctic and Palearctic specimens and 

 in supplying the Canadian National Collection with a valuable refer- 

 ence collection of Palearctic species. The aid of these persons is grate- 

 fully acknowledged. 



The genus Scambus is widely distributed in the Northern Hemi- 

 sphere. It is best represented in the Holarctic region but is also found 

 in the Neotropic and Oriental regions. In the Nearctic region species 

 and individuals are most abundant in cooler areas, especially in Canada 

 and Alaska (except in the Arctic zone) and in the northern portion of 



i Q. Stuart W alley, Senior Entomologist, Insect Systematics and Biological Control Unit, Entomology 

 Division, Ottawa, Canada. Contribution No. 3861, Entomology Division, Science Service, Department 

 of Agriculture, Ottawa, Canada. 



