lOO PSYCHE [October 



on the floor of the beak within two longitudinal chitinous ridges separated by a dis- 

 tance equal to one third the diameter of the beak and extending backward to the 

 head. These would seem to represent the fusion of the gula at its lateral edges 

 with the genae, and thus to mark the position of gular sutures. Thus the gula 

 would seem to be better marked off from neighboring sclerites than these are from 

 each other. 



Grateful acknowledgment is due Miss Mary E. Murtfeldt for specimens of dif- 

 ferent species of Balaninus; to Miss Elizabeth Andrews for the use of preparations; 

 and especially to Professor J. G. Needham, whose kind advice and daily assistance 

 made these studies not only possible, but also very pleasant. 



Biological Laboratory, 

 Lake Poorest College. 



BIBLIOGRAPHY. 



Hamilton, John. 



1873. Balaninus — Its Food Habits. Canad. Entom. Vol. XXII, pp. i-S, 1890, i fig. 

 Horn, G. H. 



1873. Kev to the species of Balaninus. Proc. Amer. Philos. Soc. Vol. XIII, pp. 457-458. 

 Kolbe, H. J. 



1885. Das Rostrum in der Ordnung Coleoptera. Berl. Entom. Zeitschr. Band XXIX, 

 pp. 80-83. 

 LeConte, J. L. and Horn, G. H. 



1876. The Rhjncophora of America north of Me.xico. Proc. Amer. Philos. Soc. vol. 

 XV, pp. i-xvi and 1-455- 

 Murtfeldt, Mary E. 



1894. Acorn Insects, Primary and Secondary. Insect Life. Vol. VI, pp. 318. 

 Needham, J. G. 



1900. Some general features of the metamorphosis of the tiag weevil, Mononychus vul- 

 peculus Fabricius, Biological Bulletin. \o\. I, pp. 179-191, 10 figs. 

 Smith, John B. 



An essay on the development of the mouth parts in certain insects. Trans. Amer. 

 Philos. Soc. Vol. XIX, pp. 175-198, 3 pis. 



