20 BULLETIN 123, UNITED STATES NATIONAL MUSEUM. 



8. RHYACIONIA FRUSTRANA (Comstock). 



(Fig. 53.) 



Retmia frustrana Comstock, Rept. U. S. Dept. Agr. for 1879, 1880, p. 236, — 



Packakd, Fifth Report U. S. Ent. Com., 1890, p. 745. 

 Evetria frustrana Feknald, in Dyar'List N. Amer. Lepid., no. 4998, 1903. — 



Baknes and McDunnough, Clieck List Lepid. Bor. Amer., no. 6760, 1917. 



This species is known in economic literature as the " Nantucket 

 pine moth," It is our commonest and on the whole the most de- 

 structive pine moth we have — on account, chiefly, of its abundance 

 and wide distribution. It occurs nearly everywhere east of the 

 Rockies where pines grow. It has two generations a year (moths 

 issuing during March and early April and again during June and 

 July) and its life history corresponds to that of rigidana as far as 

 we know the latter. Its favored food plant in the east is the com- 

 mon scrub pine {Pmus virginiana) , but it attacks and thrives on all 

 species except the white pines. For some reason these seem to be 

 immune. 



Male genitalia figured from specimen in National Collection from 

 Morristown, Pennsylvania (reared from Pinus taeda, April, 1915, 

 under Hopk, U. S. no. 12169(?, Heinrich, collector). 



Distribution according to specimens in National Collection, Ameri- 

 can Museum, and collection Barnes: Florida, Texas, Georgia, Ala- 

 bama, South Carolina, West Virginia, Virginia, Pennsylvania, Dis- 

 trict of Columbia, New Jersey, Massachusetts. 



Alar expanse. — 9-15 mm. 



Type. — In collection Cornell University. 



Type locality. — Massachusetts, 



Food plant. — Pi/nus, spp. 



9. RHYACIONIA FRUSTRANA BUSHNELLI (Busck). 



(Fig. 48.) 



Evetria hushnelU Busck, Proc. Ent. Soc. Wash., vol. 16, 1914, p. 144. — Baknes 

 and McDunnough, Checli List Lepid. Bor. Amer., no. 6773, 1917. 



Busck described this as a separate western species distinct from 

 the eastern frustratia. After several years' rearings of both forms, 

 during which I have succeeded in producing a typical hushnelU 

 artificially by inducing our smaller native frustrana to oviposit on 

 western yellow pine (P. ponderosa) and rearing through on that 

 tree, and after comparison of the genitalia of several specimens, I 

 am convinced that it is nothing more than a local food plant race. 

 There are, in fact, no consistent characters upon which to separate 

 the two. On account of its great economic importance in the sec- 

 tions of the West where it occurs, I am retaining Busck's name as a 

 racial designation. I have seen it in the West only in places where 



