FOOD PLANTS OP THE GIPSY MOTH IN AMERICA. 15 



Hazelnut (Corylns americana Walt.). 



This is a favored food plant for all stages of the larvae, although feeding is 

 heavier during the first four stages. 



In the laboratories the feeding in trays was general in all stages and male 

 and female moths were reared from larvae started in the first stage. 



Beaked Hazelnut (Corylus rostrata Ait.). 



Not as common as the above species. Field observations same as for 

 C. americana. 



Laboratory experiments had to be discontinued after the larvae reached the 

 third stage because the shrubs were sprayed with poison. 



Hemlock (Tsuga canadensis [L.] Carr.) 



This evergreen is capable of supporting life in all stages of the gipsy-moth 

 larvae. At the Worcester laboratory, Mr. Collins reared 2 males and 1 female 

 from the two trays of first-stage caterpillars. At the Melrose Highlands 

 laboratory no adults were reared. 



The field observers note feeding in all stages on the foliage, but in the first 

 stage it is the new growth only. The feeding increases in intensity with each 

 successive stage. In the field few adults develop when this tree is the exclusive 

 diet of the gipsy-moth larvae. (PI. V.) 



Bitternut Hickory (Hicoria cordifornvis [Wang.] Britton). 



No field observations were made on this hickory. 



In the trays the larvae fed quite freely in the first three stages, but the foliage 

 appeared somewhat distasteful to them in all stages. 



The tree will doubtless sustain the caterpillars through life, but is not a 

 favored food plant. 



Mockernut Hickory (Hicoria alba [L.] Britton). 



This seems to be the most favored species of the hickories. Mr. Shinkwin 

 reports nearly total defoliation of a few trees. Feeding is most noticeable in 

 the early stages. 



In the trays, first-stage larvae were reared to the fifth stage only. 



In heavy infestations, in a mixed growth, this tree may be severely defoliated. 



Pignut Hickory (Hicoria glabra [Mill.] Britton). 



Pignut hickory has been watched by all the observers and slight feeding upon 

 it has been noted in all stages. All are of the opinion that it is an unfavorable 

 food plant. The first-stage larvae begin feeding upon the bud scales and follow 

 up by eating holes in the new unfolding leaves. 



In the trays at Melrose Highlands started with first-stage larvae, male moths 

 were obtained. At no time was the feeding free, and growth was very slow. 



Shagbark Hickory (Hicoria ovata [Mill.] Britton). 



Shagbark hickory is eaten by the gipsy-moth larvae less than the other 

 hickories. The field observers report considerable feeding on the bud scales and 

 after these drop the feeding diminishes. All stages have been reported feeding 

 upon it sparingly. 



