NOV "" ''^''15 



PSYCHE 



VOL. XXII OCTOBER, 1915 No. 5 



NOTES ON THE ONTOGENY OF THE GENITAL TUBES 

 IN COLEOPTERA. 



By F. Mum, 



Hawaiian Sugar-Planters Association Experiment Station, 



Honolulu, Hawaii. 



In 1912 Dr. Sharp and I, after an extensive anatomical study of 

 the male genital tube of Coleoptera, published ^ the conclusions 

 we arrived at, along with details of this organ in most of the families 

 of Coleoptera. Upon my return to Honolulu I started a series of 

 observations on the development of this organ to see if the con- 

 clusions we had arrived at by anatomical studies could be sus- 

 tained. Field work in the Orient took me away from Honolulu 

 before I could finish this work and my notes remained unpublished; 

 similar reasons prevent me from completing the work now, but 

 as my observations may throw some light upon this subject I 

 publish the following resume. 



My observations were made upon Rhabdocnemis ohscurus, 

 CarpophUns humeralis and Ccplophora inocqualis, and a few on 

 Opairinn seriatum. Unfortunately the first three all have "ring- 

 shape" tegmina and are highly specialized forms, and the observa- 

 tions on Opatrum were not extensive enough to demonstrate the 

 development of the tegmen. It is to be hoped that a detailed 

 study of the ontogeny of a more generalized "trilobe" form will 

 be made. 



In the early stages of the male pupa of these species the testes 

 are attached, each by a fine testicular thread to a small mass of 

 cells between the ninth and tenth sternites (la). This cellular 

 mass forms an invagination (genital invagination) of the hypoderm 

 of the developing imago; it increases in size and the bottom grows 



1 Trans. Ent. Soc, Lond., 1912; III, 477-642: figs. 1-239. 



