THE ALFALFA CATERPILLAR. 17 



July 23. Following this the intestinal disease attacked the larvae 

 so generally that Mr. Wilson found it impossible to continue genera- 

 tion records. Nevertheless, he states in his field notes that a fourth 

 generation was out by the latter part of August. We thus see that 

 there are in the colder sections of the country two generations an- 

 nually and in the extreme warmer sections at least six and possibly 

 more generations each year. 



FOOD PLANTS. 



Alfalfa seems to be the favorite food plant, but there are quite 

 a number of others. The two buffalo clovers, Tri folium reflexum 

 and T. stoloniferum, were probably the original native food plants. 

 For some years the species was thought not to live upon red clover 

 (T. pratense), but Mr. E. H. Gibson, at Greenwood, Miss., and Mr. 

 W. H. Larrimer, at Nashville_, Tenn., proved conclusively that it 

 does attack red clover. They collected both eggs and larvse from red 

 clover and reared them to adults. During the summer of 1913 the 

 writer collected the larvse feeding upon few-flowered Psoralea (Psora- 

 lea tenuiflora) at Koehler, N. Mex., and Mr. Larrimer, at Nashville, 

 made some interesting experiments, besides those on red clover. 

 Using larvse that hatched indoors, he reared them from the following 

 plants that had not already been reported as food plants: Alsike 

 clover (T. hybridum), soja bean (Glycine hispida), Canadian field 

 peas (Pisum sativum) , and hairy vetch (Vicia saliva), Repeated 

 attempts to rear them on cowpeas (Vigna sinensis) resulted in fail- 

 ure. He says : " On hairy vetch they seemed to thrive exceedingly 

 well and completed their life history in a shorter period than on any 

 other food plant." In July, 1910, the writer found larvse feeding 

 on sweet clover (Melilotus alba), which, strangely enough, they 

 seemed to prefer to a patch of alfalfa growing close by. Eggs were 

 observed to be very numerous upon the leaves of the sweet clover 

 at the same time. Besides alfalfa and the buffalo clovers., Scudder 1 

 has recorded Hosackia, ground plum (Astragalus caryacarpus) , and 

 A. crotalarice as food plants. The adults visit blooming plants for 

 nectar, and they have been reported, doubtless erroneously, as feed- 

 ing upon many of these. The butterfly is known to oviposit on 

 toothed medicago or bur clover (Medicago hispida). Mr. E. H. 

 Gibson, at Greenwood, Miss., reported females ovipositing on coffee 

 weed (Sesban macrocarpa), which they curiously preferred to red 

 clover growing near by. 



1 Scudder, S. H. The Butterflies of the Eastern United States and Canada, v. 2, Cam- 

 bridge, 1889, p. 1132. 



48305°— Bull. 124—14 3 



