6 BULLETIX 843, V. S. DEPARTMENT OF AGRICULTURE. 
in their dietary. From an economic standpoint it is a potential pest 
of the type of the Colorado potato beetle and the boll weevil and it 
is singular that it has never migrated to any noticeable extent as have 
those pests, since it is probably capable of extended nights. One 
reason that may be assigned for this is its practical limitation to a 
single food plant, while the potato-feeding insect infests virtually 
all of the Solanaceae. including the weeds, and is capable of breeding 
continuously on all species of Solanum and probably on other genera. 
There is no reason to suppose that this insect may not by flight in- 
crease its present range materially some time, although not neces- 
sarily in the near future. Its further dissemination, however, would 
doubtless be slow and never as rapid as in the case of the compara- 
tively fleet-winged and more adaptable Colorado potato beetle. The 
reasons, then, for its failure to have become more widely distributed 
are : Its limitation to a single food plant and its probable incapacity 
for protracted night with the wind. Moreover, it is probably not 
capable of inhabiting such varied climates as is the Colorado potato 
beetle, a species which seems to have no respect for life zones but 
which thrives equally well from subtropical southern Texas to boreal 
Manitoba. 
In the case of the Colorado potato beetle it can not as yet be defi- 
nitely stated, as some authors have assumed, that it breeds wherever 
potatoes are grown, but it is perfectly capable of doing so. and it may 
be that in the course of time, many years undoubtedly, the bean lady- 
bird will be distributed wherever its food plant is cultivated. 1 
Another factor which strengthens the belief that the bean ladybird 
will, in the course of time, become more widely disseminated is its 
very close relationship, both structurally and biologically, to the 
squash ladybird {E pilachna ~borecdis Fab.), which ranges from South 
America northward through Central America. Mexico, and the An- 
tilles, along the Mexican and Atlantic seaboard States to Maine and 
Canada. Obviously the squash-feeding species has a similar tropical 
origin, beginning farther southward and extending much farther 
northward. Instead of progressing straight northward it has fol- 
lowed more nearly the coastal lines and has a totally different distri- 
bution in the United States, being somewhat restricted to the East 2 
just as the bean ladybird is restricted to the Middle West. 
The present distribution of this species as outlined in the map 
would indicate that we may expect its establishment some time in 
the future in near-by counties in the States of Utah. Wyoming. Ne- 
1 The predacious ladybird ITippodamia convergcns Gu6r. is capable of accommodat- 
ing itself to practically all climes and countries, with the exception of areas where the 
temperature is so high or so low tbat few forms of plant and insect life are able 
to surviv< . 
- It occurs, though not as a pest, in certain other regions remote from the region speci- 
fied, e. g., in Kansas and Arkansas. 
