366 



Shortly after the publication of Horn's "Revision," which was 

 based upon external characters alone, a notable contribution to our 

 knowledge of Phyllophaga was made by John B. Smith (1889), who 

 demonstrated the great taxonomic value of the genital characters in 

 the group, and published a series of figures showing these characters 

 for the various species. Smith's figures have been immensely useful 

 to entomologists who have used these characters, but unfortunately, 

 they were designed to supplement Horn's work rather than for in- 

 dependent use, and were published without any accompanying synoptic 

 tables. For this reason they are available only indirectly, through the 

 index, for verifying determinations based upon external characters 

 made first from Horn's tables, and they have not been used as gen- 

 erally as they should have been. 



Smith's work was based upon that of Horn, and made no advance 

 in nomenclatural accuracy such as the use of the genital characters 

 had made possible, for, as Smith states in his introduction, he had 

 no opportunity to verify by reference to the types Horn's determina- 

 tions of the species described by earlier authors. The insufficiency of 

 the external characters when used alone, makes it no reflection upon 

 the thoroughness of Horn's work to say that these determinations 

 were not always correct, and, indeed, Dr. Horn's statements quoted 

 above show that he freely admitted such a possibility himself. 



Since our present unsatisfactory knowledge of Phyllophaga is due 

 primarily to the lack of means for the ready and accurate determina- 

 tion of the species, the writer determined, as the first step toward the 

 accomplishment of his original purpose, to make a thorough systematic 

 study of the group, and to prepare tables and figures such that collect- 

 ors anywhere may make accurate determinations of their species with 

 ease and certainty. In this way it is hoped so to encourage the study 

 of the group that local lists may multiply rapidly and accurate data 

 increase, until the group may serve, possibly in a few years, as a 

 basis for the biological generalizations to which it promises to lend 

 itself so effectively. 



Because of the more urgent need for such a treatment of the 

 "May beetles" of that region, and because it was desired to stimulate 

 collecting there as early as possible, the species of the United States 

 and Canada were taken up first ; but it is hoped to extend the work 

 as rapidly as circumstances may permit, to include the entire range 

 of the group. 



This preliminary paper is designed to indicate the progress of the 

 work, and to present at once the changes in synonymy that a thorough 

 study of the types has shown to be necessary. 



