FOOD PLANTS OF THE GIPSY MOTH IN AMERICA. 13 



Bush Honeysuckle (Diervilla diervilla [L.] MacM.). 



This is a very common shrub along roadsides and in waste places. Mr. H. 

 W. Allen reports that it was not eaten in an infested area at Manchester, N. H. 

 It is an unfavored species. 



Narrow Dock (Rumex crispus L.). 



Mr. Bailey reports seeing first and second stage larvae feeding on this dock 

 in Pelham, N. H. But little feeding was noted, however. It is an unfavored 

 species. 



American Elder (Sambucus canadensis L.). 



This foliage was used in trays for all stages of gypsy-moth larvae up to and 

 including the fourth stage, and but very few changed to the next stage. There 

 was very slight feeding and no growth. 



Several observers have seen larvae on this species, but none note any feeding 

 beyond a few pinholes or notches in edges of the leaves. It is an unfavored 

 species. 



American Elm (Ulmus americana L. ). 



All stages of the larvae were noted feeding on elm, but usually to a limited 

 extent. In heavily infested areas, where other species are completely de- 

 foliated, the elm shows much feeding, but it does not appear to be a favorite 

 food if other species are available. In the trays, adults were reared from 

 larvae started in the first stage on elm foliage. The growth, however, was 

 slow and the feeding light. 



The preference for this food seems to have changed in the last 20 years. 

 In the early nineties the elms were considered favored food. In the spring 

 and summer of 1894 elm was the food used in nearly all the experiments car- 

 ried on in the Massachusetts State Laboratory, then located in Maiden, Mass. 

 The larvae fed freely on it and grew rapidly. In the trays in 1912 it was 

 apparently distasteful to them and they were constantly searching for other 

 food. 



English Elm {Ulmus cdmpestris L. ). 



Our only knowledge on this elm is from the tray experiments. The larvae 

 fed about the same on this species as on the native elm, but none reached the 

 adult stage. A few reached the fifth stage that were started in the third 

 stage. In the open they could probably develop from the egg to the adult. 



Slippery Elm ( Ulmus fulva Michx. ) . 



Tray experiments show this to be an unfavored food plant. Few larva? 

 passed to the next higher stage while being fed upon it. 



Mr. Proctor notes slight feeding in the field in all stages where the infesta- 

 tion was heavy. 



Sweet Fern (Comq>tonia peregrina [L.] Coulter). 



Larvae in all stages have been observed feeding on this shrub and in heavily 

 infested localities defoliation has taken place. In spite of this evidence it is 

 not a favored food, and if other species are present in considerable numbers 

 the feeding is not usually heavy on sweet fern. 



Tray experiments show slow feeding and very little growth. But few larvae 

 passed to the next higher stage. 



