March 1S91.J 



PSYCHE. 



45 



all these respects it agrees with the re- 

 lated corn root- worm of the North. 



I have not observed thus far that its 

 abundance has any relation to the land 

 having been previously in corn. The 

 northern species, it will be remembered, 

 is commonly most abundant on old corn 

 land. Two of the worst infested fields 

 examined in 1SS9 were, one in tobacco, 

 and the other in oats, in iSSS. A third 

 field, in corn in 1SS7 and iSSS, was in 

 oats in the spring of 1SS9, these to be 

 followed the same season by a late plant- 

 ing of corn. This difference in the in- 

 juries of the two corn root-worms is to 

 be attributed to the fact that D. longi- 

 comis hibernates in the egg state in the 

 earth of corn fields, whereas D. 12- 

 fifinctata hibernates, at least in great 

 part, as an adult beetle which wanders 

 actively about in fall and spring in 

 search of food. Still, the observation 

 reported in Insect life concerning injury 

 to orchard trees planted on corn land 

 renders it probable that in some cases 

 beetles which develop in corn land 

 hibernate there. This would certainly 

 be the case at any rate if the corn was 

 very late. 



D. 12-punctata seems to be the only 

 corn root-worm of Kentucky, and cer- 

 tainly is the only generally injurious one. 

 During two seasons' collecting I have 

 not found a single specimen of D. longi- 

 cornis within the limits of the State. 



LIFE-HISTORY (FOR KENTUCKY). 



Young larvae noted on the 15th of 

 Jul}', 1SS9, were mostly grown, and 

 some had pupated in small cells in the 



earth by the 29th of the same month. 

 Adult beetles dissected at this time con- 

 tained numerous ova of relatively large 

 size. On August 3 of that summer an 

 examination of infested corn showed 

 that most of the larvae had pupated or 

 were ready to do so. No very young 

 worms were seen. One adult was taken 

 from an earthen cell where it had re- 

 cently changed from a pupa. From the 

 abundance of females with well devel- 

 oped ova about fields at this time it 

 seemed probable there was to be a sec- 

 ond brood. Subsequent search in the 

 fields did not reveal young larvae there, 

 and towards the end of August the fe- 

 males disappeared, and none were ob- 

 served with developed eggs during the 

 remainder of the season. 



The eggs of these females were cer- 

 tainly not deposited freely among corn 

 that was damaged by the early brood of 

 larvae. What then became of them? 



Several larvae and pupae, perhaps 

 from eggs laid by these females, were 

 found among injured corn late in sum- 

 mer, but thorough search at different 

 times showed them to be rare, and I was 

 for a time led to think the species might 

 be single brooded like the related D. 

 longicomis. But on the first of Novem- 

 ber, 18S9, the discovery in a field of 

 late-planted corn of numerous larvae to- 

 gether with pupae and recently trans- 

 formed adults, gave unquestionable 

 proof of at least two annual broods of 

 the insect for this locality. The exam- 

 ples collected at this time were chiefly 

 grown larvae, contracted and ready for 

 pupation, with occasional individuals 



