FOUR RHYNCHOPHORA ATTACKING CORN IN 

 STORAGE 



By Richard T. Cotton 1 



Scientific Assistant, Stored-Product Insect Investigations, Bureau of Entomology, 

 United States Department of Agriculture 



INTRODUCTION 



Of the numerous insect enemies of stored corn there are four belonging 

 to the suborder Rhynchophora, or weevils, that are to a greater or less 

 extent of economic importance in the United States. Of these four, one 

 has received but little attention from economic entomologists, while of 

 the remaining three much has been published, but comparatively little 

 careful work has been done with the immature stages. 



It is the purpose of this paper to present accurate drawings of the 

 immature stages of these weevils, together with carefully prepared 

 descriptions and keys, so that the various species may be readily dis- 

 tinguished in whatever stage they may be found. 



The weevils under discussion represent two different families, Anthri- 

 bidae and Curculionidae, and three different genera, Araecerus, Caulo- 

 philus, and Sitophilus, two of the weevils belonging to the last genus. 



KEY TO ADULTS 



a. Beak short and broad. 



b. Robust beetle, antennae inserted in small foveae upon the upper surface 



of base of beak, last three segments of antennse forming a loose club. 



Araecerus fasciculaius DeG. 

 bb. Slender, elongate beetle, antennae inserted at middle of beak, last few 



joints forming a compact club Caulophilus latinasus Say. 



aa. Beak elongate and slender. 



c. Thorax with coarse, sparse, elongate punctures, wings lacking. 



Sitophilus granarius L. 

 cc. Thorax with coarse, deep, very dense punctures, wings present. 



Sitophilus oryza L- 

 KEY TO MATURE LARV^ 



a. Body slender, elongate, supplied with some or many long hairs, abdominal seg- 

 ments with hypopleurum not subdivided, mandibles armed dorsally with a 

 pair of bristles set close together. 



b. Larger, 4.5 to 6 mm. in length, body profusely covered with long hairs. 



Araecerus fasciculatus DeG. 



bb. Smaller, 2 to 2.5 mm. in length, body sparsely provided with long 



hairs Caulophilus latinasus Say. 



1 The writer wishes to express his gratitude to Dr. Adam G. Boving, of the Bureau of Entomology, United 

 States Department of Agriculture, for his kindness in extending much valuable aid and advice in the study 

 of the larval forms and the preparation of the technical descriptions. 



Journal of Agricultural Research, (605 ) Vo1 - xx - No - 8 



Washington, D. C Jan. 15. 1921 



w k Key No. K-90 



