104 



ON THE HABITS AND LIFE HISTORY OF DIABROTICA 12-PUNCTATA 



OLIV. 



By C. V. KiLEY. 



In Psyche for February and March, 1891, Prof. H. Gariiian, of the 

 Kentucky Agricultural Exijeriment Station, gives a detailed and lengthy 

 sununary of the literature on the subject of the habits of this well-known 

 enemy of cucurbitaceous plants, and follows with a careful account of 

 his observations upon its early states, showing that during 1889-'90 the 

 damage of the larvae to corn attracted attention over a wide area of 

 country, including the States of Virginia, Alabama, Mississippi, Louisi- 

 ana, Arkansas, Kentucky, Illinois, and Ohio. His own observations 

 began July 15, 1889, and in brief may be summarized as follows : 



.^.-/4/^ M 



^-^>' i\ 



Via. 5.— Diabrotica 12punctata: a, egg— greatly enlarged: b, lar%-a; c. corn-stalk showing jjimctures; 

 d, jmpa: (', adult — b. d, and e enlarged (original). 



The young larvae were noted upon July 15, 1889, and became full 

 grown by the 29th of the same month, they having pupated in small 

 cells in the earth at the latter date. Adult beetles dissected at this 

 time contained eggs of a relatively large size. August 3 most of the 

 larvae had pujiated. No very young worms were seen, and one adult 

 was found. A second brood was expected, but towards the end of 

 August the females had disappeared and none were observed with 

 developed eggs during the remainder of the season. Larvae and pupae 

 were rare from this time on until the first of Xovember, Avlien, in a field 

 of late-planted corn, numerous larvae, pupae, and recently transformed 

 adults were found. Observations made by Mr. Lugger showed that the 

 insect breeds upon the roots of Rudbeckia, and Professor Garman sur- 

 mises that the majority of the second brood will be found to breed upon 



