2i6 Journal of Agricultural Research voi. xxn.No4 



CastanEa. Experiment XXV^ — ^September 20, 1916, fifteen larvae, 

 one-half to nearly full grown, were transferred from sumac to chestnut 

 cut durmg March. July 10, 191 7, one adult emerged, the only one 

 from these transfers. 



HicoRiA. Experiment XX V^ — July 25, 19 16, eleven larvae about 

 half grown were transferred from sumac to hickory. August 9, eleven 

 more were transferred. The larvae seemed to do quite well and by winter 

 many had made pupal cells. 



During June, 191 7, twelve adults emerged and were caged on pieces 

 of hickory cut the preceding June, August, April, and February. No 

 infestation occurred in any of the wood. The cage accidentally dried for 

 a two- week period while the adults were ovipositing and this may account 

 for the failure of infestation, as they require considerable moisture. 



In June, 191 7, adults from sumac were isolated in various cuts of 

 hickory but no infestation occurred. 



July 23, 191 7, twenty-seven larvae were transferred from sumac to 

 hickory cut in September, 19 16, and March, 191 7. The larvae did well 

 and the following May and June 10 adults were reared and caged on 

 hickory sticks cut in September, 19 17. On several of these sticks bands 

 of thin outer bark of sumac were tied. 



The adults oviposited only on those sticks and at those places where 

 the sumac bark was tied. July 30 they had not yet bored beneath the 

 hickory bark proper, but by fall nearly all had entered the bark. Only 

 one larva transformed to an adult in the summer of 19 19. One adult 

 emerged in 1920. Several larvae did not transform but continued feeding 

 beneath the bark during the summer of 19 19. 



LIOPUS ALPH.\, HICORIA FORM. EXPERIMENT XXX 



The Hicoria form was not successfully continued in confinement until 

 the summer of 191 7. It requires wood cut in August, dried in the air for 

 a month or so, and then placed on damp earth over winter. In addition 

 the adults must be well fed on fungus spores {Endothea parasitica was 

 used) before they will oviposit. 



It was again continued in hickory in 1918, 191 9, and 1920. During 

 June, 19 19, many adults were caged on sumac branches and eggs were 

 deposited. Three larvae lived to construct mines under the bark, but 

 these died before November. 



CONCLUSIONS 



From the foregoing experiments and the fact that each of these two 

 color forms has been taken only in the host given, it is evident that each 

 has become restricted to that host and shows a strong predilection for 

 it. Even after having fed for one year in a new host (Hicoria) adults 

 developing from them showed a preference, in their oviposition, for that 

 part of the hickory twig surrounded by Rhus bark. A fairly high mortal- 

 ity of larvae occurred after transfer to the new host. 



