THE BIOLOGY OF THE ALDER FLEA-BEETLE. 271 



in clusters on the under side of the leaves. Specimens were 

 referred to Mr. C. W. Leng of New York City, who kindly 

 determined them as undoubtedly Altica bimarginata Say. 



All of the data on pages 253-270 appertain to the alder race. 



Gibson (1913 p. 6) recorded this species as feeding on alder, 

 willow, and poplar. Essig (1915 p. 266) reported this insect 

 from alder, willow, poplar, and cottonwood. 



The following tables record a few food plant tests which 

 were made with the larvae and adults of the 2 races. The tests 

 were made as follows : 6 larvae or adults were kept in a clean 

 shell-vial without food for 24 hours; then an uninjured leaf of 

 the plant to be tested was introduced, and the insects were left 

 undisturbed for a second 24 hours; at the end of that time the 

 leaves were examined, and a record made as to whether they 

 had been considerably eaten, slightly eaten, or left untouched. 



Altica bimarginata. (Alder race.) Food-plants of adult. 



(i) Eaten readily. 



Willow, Salix sp. near nigra Marsh, S. cordata Muhl., S. rostrata 

 Richards; alder, Alnus incana (L.) Moench. 



(ii) Eaten slightly. 



European gooseberry, Ribes Grossularia L. 



(iii) Refused. 



Balsam poplar, Populus balsamifera L. ; gray birch, Betula pop- 

 ulifolia Marsh ; white elm, Ulmus americana L. ; cultivated rose, 

 Rosa sp. ; wild red cherry, Prunus Pennsylvania L. f. 



Altica bimarginata. (Poplar race.) Food-plants of adult. 



(i) Eaten readily. 



Willow, Salix cordata Muhl.; balsam poplar, Populus balsamifera 



L. ; alder, Alnus incana (L.) Moench. 

 (ii) Eaten slightly. 



\Yhite elm, Ulmus americana L. 

 (iii) Refused. 



Gray birch, Betula populifolia Marsh; wild red cherry, Prunus 



pennsyhanica L. f . ; red osier dogwood, Cornus stolonifera Michx. 



Altica bimarginata. (Alder race.) Food-plants of larva. 



(i) Eaten readily. 



Willow, Salix sp. near nigra Marsh, S. cordata Muhl.; aspen pop- 

 Richards; alder, Alnus incana (L.) Moench. 



(ii; Refused. 



Balsam poplar, Populus balsamifera L. ; wild strawberry, Fragaria 

 virginiana Duchesne; red osier dogwood, Cornus stolonifera Michx. 

 Altica bimarginata. (Poplar race.) Food-plants of larva. 



