58 R. W. Dawson 



during the progress of this work. Four of these have already 

 been published by the writer in his studies on the genus 

 Serica; two are now in press in a short revision of the genus 

 Bolbocerosoma by the writer and Mr. McColloch, and one in 

 the genus Lygerodes has been assigned to Mr. Casey for de- 

 scription. 



In the following pages the writer has tried to continually 

 keep in mind the needs of the beginning student and has 

 spared no pains to make the tables easy and workable, the 

 most evident and readily described characters available being 

 employed in constructing the tables, regardless of their funda- 

 mental taxonomic value. Since then, the statements of the 

 fundamental group characters have thus largely been dis- 

 associated from the generic tabulation it has seemed desirable 

 to incorporate them in the body of the text under the major 

 headings. 



The student should not gain the notion that the Scara- 

 baeidae have been fully and adequately studied, and that little 

 new is to be added to the knowledge of the family, for such 

 is far from the situation. Perhaps the most striking ex- 

 ample of the inadequacy of the literature is the case of the 

 genus Serica, where the writer has found more than fifty un- 

 described species. In fact the presentation of this review 

 has long been delayed because of the impossibility of naming 

 the Nebraska species in this genus until the main facts con- 

 cerning it were worked out for the whole of the North 

 American fauna. Much is yet to be learned concerning the 

 following Genera: Trox, Serica, Diplotaxis, Phyllophaga, 

 Polyphylla, Hoplia, Anomala, Cyclocephala, Ligyrus, Eu- 

 phoria, Cremastochilus and Trichius. Any or all of these 

 genera could well be restudied monographically. 



The family Scarabaeidae is a remarkably interesting one 

 for the systematist. He can revel in studies of individual 

 and subspecific variation, and the correlations of variation 

 with geographical distribution in such genera as Hoplia, 

 Phyllophaga, Ano7nala, and Euphoria until he becomes con- 



164 



