AMERICAN COLEOPTERA. 155 



Descriptions of some monstrosities observed in North 

 American Coleoptera. 



BY HORACE F. JAYNE. 



The accumulation of material iu some of the larger collections of 

 Coleoptera of our fauna has suggested that a description of the more 

 marked monstrosities might be interesting, and aid at some future 

 time in throwing light on points of development not yet understood. 

 I have, therefore, iu the following pages, described and figured those 

 monstrosities which M. Mocquerys of Rouen, in his excellent work 

 on Abnormal Coleoptera, calls " Monstrosities by Excess." Deformities 

 by deficiency or incomplete development have not been considered as 

 they do not seem of suflScient importance, and point only to accidents 

 happening to the insects while in the larvae or pupa3 stage. 



I desire to return my sincere thanks to Dr. Horn for the free use 

 of his collection and library, for many suggestions and for kindly 

 revising these pages ; also to Dr. LeConte for the loan of specimens 

 from his cabinet, and to Dr. Hagen for the use of specimens belono-ino- 

 to the Museum of Comparative Zoology at Cambridge. 



Calosoma triste, Lee. 



Fig. 1 represents a monstrosity on the right antenna of a specimen 

 of Calosonia triste, Lee. It consists in the sixth joint bearing two 

 branches of five joints. Fig. 1 a, shows the antenna greatly enlaro'ed. 

 The first three joints are normal; the third a little dilated at apex. 

 The fourth is normal in length but is one-half broader at apex. 

 When viewed from above it is distinctly pyriform. The fifth joint is 

 also of normal length but twice the width of that of the left side and 

 slightly broader at apex. The sixth joint is pentagonal in form, in 

 its widest place as wide as long. The apex is obliquely truncate on 

 its inner and outer angles, presenting two unequal faces for the inser- 

 tion of the two branches. The inner or posterior facet is much smaller 

 and from it arises that branch with the joints exactly resembliuf the 

 normal antenna. The anterior or outer facet is larger and ^ives 

 insertion to an anterior or outer branch of five joints; the first bein" 

 short and thick the others similar to the corresponding normal joints 

 but smaller. 



The specimen is in Dr. Horn's Cabinet. Collected in California. 



