1919] 



Metcalf — A Malformed Leptinotarsa decemlineata 



in Drosophila as due to a lagging sex-chromosome. As a full ac- 

 count of his researches has not yet been published, I am unable 

 to undertake the task of harmonizing it with what I conceive to be 

 the conditions in the Formicidse. 



,4: 



A MALFORMED LEPTINOTARSA DECEMLINEATA. 



By C. L. Metcalf, 

 Ohio State University. 



The two accompanying illustrations show an interesting 

 and peculiar malformation of a specimen of the Colorado potato 

 beetle. The specimen was col- 

 lected by Mrs. Cleo F. Metcalf 

 at Orono, Maine, August 17, 

 1916. It was taken in com- 

 pany with many normal indi- 

 viduals feeding upon potato. 

 Unfortunately its peculiar con- 

 dition was not noted until it 

 had been killed. A prolonged 

 search failed to reveal any 

 other specimens in any way 

 abnormal. The chief purpose 

 in describing it here is to 

 record for the curious natural- 

 ist, who does not lack a sense, 

 of humor, a freakish, though 

 not uncomely, product of one 

 of nature's sportive moods. 



The visible abnormality con- 

 sists of a deep, V-shaped ex- 

 cision of each elytron extend- 

 ing from the apex to about 

 the basal third of the normal 

 elytron. The elytra are a little 

 foreshortened ; the middorsal 

 line is nearly straight in side 

 view; and the usual convexity 



covering the tip of the abdomen is entirely wanting, leaving the 

 abdomen exposed from behind. 



Fig. 1. Malformed Leptinotarsa decem- 

 lineata, showing anomaly in structure and 

 pattern of the elytra; below, same in lateral 

 view. About three times natural size. 



