10 PROCEEDINGS OF THE NATIONAL MUSEUM vol. loi 



at different heights from airplanes, has taken 25 specimens of 

 Myockrous in spring, summer, and fall months, and it was apparently 

 one of the most abundant of chrysomelids in his flights over Tallulah, 

 La. Adults are frequently brought into the United States on planes, 

 and in shipments of fruit and vegetables from Central American and 

 Caribbean regions. 



ACKNOWLEDGMENTS 



I vp^ish to express my gratitude to the numerous individuals, many 

 of them representing institutions, for lending me specimens and even 

 going out and collecting beetles for me, as well as for making tedious 

 comparisons of types. Particular mention should be made of H. E. 

 Hinton, British Museum of Natural History; Otto Lundblad and 

 Eene Malaise, Stockholm Museum of Natural History ; W. J. Brown, 

 Department of Agriculture, Ottawa, Canada; F. Monros, Institute 

 Miguel Lillo, Tucuman, Argentina ; R. H. Beamer, University of Kan- 

 sas; J. C. Bequaert, P. J. Darlington, and Floyd Werner, Museum of 

 Comparative Zoology; C. E. Mikel, University of Minnesota; H. B. 

 Mills, Montana State College ; H. C. Severin, South Dakota State Col- 

 lege ; E. C. Van Dyke, California Academy of Sciences ; B. E. White, 

 Merced, Calif. ; as well as my colleagues at the U. S. National Museum, 

 W. H. Anderson, the late H. S. Barber, L. L. Buchanan, and E. A. 

 Chapin. 



KEY TO THE SPECIES OF MYOCHROUS 



NORTH OF MEXICO 



1. Sides of thorax not distinctly 3-toothed 2 



Sides of thorax distinctly 3-toothed 5 



2. Sides of prothorax with two distinct angles, one before middle, the 



other behind middle 3 



Sides of prothorax with one distinct angle before middle 4 



3. Elytra densely covered by broad brown-and-white scales, easily 



rubbed off, showing round punctures (Brownsville, Tex.). 



paiixillus Schaeffer 

 Elytra very inconspicuously scaly, the scales very short and not 

 hiding punctures below, punctures not round but triangular or 

 stellate (North Dakota) severini, new species 



4. Elytra densely covered with short, very broad, truncate squamules, 



punctures of thorax distinct, not very confluent although in longi- 

 tudinal lines (Canada to Texas) squamosus LeConte 



Elytra with scales usually not so dense as to hide completely the 

 sculpture below, scales longer and not so wide, punctation of 

 prothorax finer, not at all distinct, but in dense, longitudinal lines 

 (Iowa to Texas) intermedius, new species 



5. Long slender beetles, with prothorax as long as wide, covered by 



rather broad, long scales (California, Arizona to Idaho) 6 



Broadly oblong beetles, with the prothorax usually broader than 

 long, and usually with finer scales (with one exception occur- 

 ring east of Arizona) 7 



