214 Journal of Agricultural Research voi. xxn.No. 4 



experiment of May 23, 19 18. When examined on July 18, both woods 

 were heavily infested. Redbud was unintentionally omitted. 



This experiment was repeated in 19 19, two pieces of hickory, one of 

 dogwood, and one of redbud being used. Two cages were prepared; in 

 one, a single pair was isolated, the resulting infestation being, hickory 

 heavily infested, dogwood and redbud uninf ested ; in the other cage three 

 pairs were isolated, the resulting infestation being, hickory and dogwood 

 both heavily infested, redbud uninf ested. 



NEOCLYTUS ERYTHROCEPHALUS, CORNUS FORM. EXPERIMENT XII 



June 13 to 15, 1916, adults emerging from dogwood at Falls Church* 

 Va., were recaged on this wood cut in April, 1916. A good infestation 

 was secured. June, 1917, the colony was continued in dogwood and two 

 pairs of adults were isolated in a cage containing dogwood and tulip cut 

 May 30 and hickory and redbud cut April 18. 



In July it was found that both redbud and dogwood contained few 

 larvae while hickory and tulip contained none. 



For some unknown reason the larvae continued in dogwood did not 

 develop very well, and in 1918 only one female emerged. May 25, 1918, 

 this female was mated with a male from hickory and isolated in a cage 

 containing dogwood, hickory, and redbud cut April 15. 



July 18, 1 91 8, the dogwood was heavily infested, the redbud lightly, 

 and the hickory contained one larva. 



In June, 1919, one pair was caged on pieces of dogwood, redbud, and 

 hickory. An examination in July showed dogwood to be very heavily 

 infested, the redbud and hickory containing seven and six larvae, respect- 

 ively. 



NEOCLYTUS ERYTHROCEPHALUS, CERCIS FORM. EXPERIMENT XIII 



Redbud infested with this species was collected at Hummelstown, 

 Pa., by J. N. Knull and sent to Falls Church, Va., in April, 1916. Adults 

 emerged in June and the colony was continued in redbud. June, 1917, 

 the colony was again continued in redbud, and two pairs of adults were 

 isolated in redbud and hickory cut in April and tulip and dogwood cut 

 in May. 



An examination in July showed the redbud to be heavily infested; 

 the dogwood and hickory contained several larv^ae, and the tulip none. 



In May, 191 8, two pairs were again caged on redbud, dogwood, and 

 hickory, all cut April 15. In July it was found that the redbud and the 

 dogwood were heavily infested while the hickory contained but three 

 larvae. 



The same experiment was repeated in 1919, and the results showed the 

 redbud to contain eight larvae, the dogwood five, and the hickory two. 



The selection tests of 191 7 were all carried out with the same quantity 

 of wood ; in each case the pieces were i }{ inches in diameter and i foot 

 long. Bach cage contained two pieces of the wood from which the 



