1940] Food Preferences of Colorado Potato Beetle 
41 
foliage of tomato plants in his garden in Belmont, near 
Cambridge, Mass. On account of this unusual occurrence 
it appeared that we might have chanced upon a mutation in 
choice of food and a part of the colony was transferred to 
one of the large screened cages 4 with a few healthy tomato- 
plants. They continued to feed and it appeared that some 
of the larger larvae had entered the soil to pupate although 
the majority died before attaining full growth. However, 
no adults of a second generation appeared in the cage and 
the soil was left undisturbed until the following summer 
which likewise brought forth no beetles. This second year 
a similar infestation occurred in Professor Castle’s garden, 
but we made no further transfers as it was evident that the 
beetles could not maintain themselves on tomato even though 
certain adults had developed a taste for it. In France Trou- 
velot and Thenard (’31) have similarly noted the disap- 
pearance of the larvae from tomato plants and they attribu- 
ted this to the difficulty experienced by the larvae in main- 
taining their foothold while crawling on the coarsely hairy 
leaf stalks. This has been later questioned, however, by 
others working in the same region. Feytaud (’23) noted 
earlier that the adult beetles in France eat tomato foliage 
avidly, a statement that could certainly not be applied gen- 
erally to the potato-beetle population in America. Quite re- 
cent studies in France substantiate this as they have shown 
that certain varieties of tomato are readily eaten while 
others are not. 
Laboratory experiments by Mclndoo (’35) showed that 
both adults and larvae are to a surprising extent attracted to 
tomato leaves when permitted to choose between potato, 
horse-nettle ( Solanum carolinense ) , S. dulcamara and to- 
mato. Although showing much irregularity, a considerable 
number (+9.6-12%) of beetles and many larva (15%) came 
to rest on the tomato leaves. As the species is unable to sur- 
vive on tomato it is clear that when tomato is as readily 
available as other acceptable species that there is a consis- 
tent weeding out in the general population of those beetles 
4 These cages were four feet square at the top and bottom with vertical 
sides eight feet high, covered completely with bronze window screening 
except on the bottom which was sunk to a depth of eight inches in the 
soil of the garden. They thus maintained the plants and insects under 
practically out-door condition throughout the year. 
