A COMPARATIVE STUDY OF THE LABIUM OF 

 COLEOPTEROUS LARVAE 



By W. H. ANDERSON 



Dcparlincnt of Entomology, University of Maryland 

 (With Eight Plates) 



CONTENTS 



PAGE 



Introduction i 



I. General discussion of the insect labium i 



Comparison of various types of labial structure 6 



II. Descriptions of labia of coleopterous larvae 7 



III. The tentorium of coleopterous larvae 24 



IV. Conclusion 26 



Abbreviations used on the figures 27 



References 27 



Explanation of plates 28 



INTRODUCTION 



The study reported on in this paper v\^as undertaken with the idea 

 of comparing the labia of coleopterous larvae and giving the proper 

 connotation to the various parts and plates thereof. The naming of 

 the divisions has been based on a study of muscle origins and inser- 

 tions. It is hoped that students of systematic entomology may gain 

 some help, either directly or indirectly, from the facts herein reported. 



The paper represents the major part of a thesis presented to the 

 faculty of the Graduate School of the University of Maryland in 

 partial fulfillment of the requirements for the degree of Doctor of 

 Philosophy. 



The author wishes to express his appreciation of the kindness and 

 help of R. E. Snodgrass and Dr. A. G. Boving, of the United States 

 Bureau of Entomology. 



I. GENERAL DISCUSSION OF THE INSECT LABIUM 



The labium of insects in its simplest generalized form consists of 

 two major divisions. These parts have been given various names by 

 previous workers, as is shown in the table following, but the most 

 logical system of terminology is that suggested by Snodgrass (1931) 

 because it results from com]iarative studies of these structures in all 



Smithsonian Miscellaneous Collections, Vol. 95, No. 13 



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