46 



PSYCHE. 



[March 1891. 



about three-fourths grown, and a few 

 pupae and recently emerged adults. 



In my paper as read at the Washing- 

 ton meeting of entomologists I stated 

 that the above facts made it seem prob- 

 able that the late brood of larvae fed in 

 part on plants other than corn. In the 

 discussion following, Prof. Otto Lugger 

 of Minnesota showed the surmise to be 

 well founded by stating that he had taken 

 pupae at the roots of one of the native 

 Compositae, — a species of Rudbeckia. 

 At my request he has since kindly given 

 me the following definite statement, 

 quoted partly from his notes : 



'' Diabrotica 12-punctata. — Sep, 3, '89* 

 found among roots of Rudbeckia sp. three 

 pupae of a chrysomelid, nearly ready to issue 

 the imago. Sep. 5, '89, ail three insects ap- 

 peared above ground in breeding cage. At 

 first white, they soon changed to the normal 

 color, excepting that the black spots were 

 only faintly visible. Sep. 7, '89, insects 

 mature, and mounted. It is the above spe- 

 cies. 



Many specimens occurred at this time upon 

 the above plant and upon Solidago and this 

 ties. The majority appeared quite fresh, as 

 if hatched quite recently. The Rudbeckia 

 grew in an old field cultivated some four years 

 ago, but grown up into a wilderness of Soli- 

 dago, Rudbeckia, thistles, etc. The nearest 

 field of corn is fully one-fourth mile from 

 this spot." 



Prof. Lugger's observation explains 

 the whereabouts of most of the late 

 brood. Very little corn is planted here 

 as late as that in which the second brood 

 occurred, so that ordinarily the beetles 

 must resort to some other plant for ovi- 

 position. Five Kentucky species of 



Rudbeckia are known, and in all prob- 

 ability the beetles which emerged from 

 the ground in this vicinity during Au- 

 gust resorted to these. The observation 

 also renders it almost certain that the 

 insect is two brooded at latitudes much 

 higher than this. 



The larvae and pupae in the field of 

 late-planted corn were followed until 

 all had completed their transformations. 

 From an excess of larvae in November, 

 the proportion was gradually changed 

 to an excess of pupae in December. A 

 short time spent digging about hills of 

 corn on Dec. 5 resulted in finding seven 

 pupae and two larvae. Subsequently 

 we experienced a most exceptional 

 period of spring-like weather, and 

 urged apparently by its influence all the 

 larvae and pupae completed their trans- 

 formations. On January 16, a close 

 search among the infested roots did not 

 reveal the presence of a single example. 

 Previous to December we had some 

 weather during which the surface of the 

 ground was frozen. If the winter sub- 

 sequently had not been so mild it is safe 

 to assume that the larvae and pupae in 

 the frozen ground would not have 

 changed to beetles until the spring of 

 1S90. 



The adult beetle has been found 

 abroad at all times when looked for 

 from July 10, 1S89, until December, 

 1S90. During the winter it is to be 

 found among rubbish in strawberry 

 beds, in gardens, and meadows. Dur- 

 ing mild days it is often awake, and 

 feeds at such times on almost any green 

 vegetation within reach. It is one of 



