23 
of ground near Mesilla, New Mexico, on which not a particle of vege- 
tation had grown for three years. Sixteen grubs were secured in a 
square foot or two of ground. These larvwe were probably A. mutabilis 
and not A. nitida. Further, the feeding of the larve upon the bran- 
arsenic mash and the efficacy of this remedy against them, as described 
later under the section on remedies, is additional evidence against the 
normal feeding on living vegetation, although it must be confessed 
that certain plant-feeding insects will also feed on this mash. 
In the celery beds above referred to the grubs were found to be fully 
as numerous in one part of the field as another, while the direction of 
the burrows had no reference to the presence or absence of living 
vegetation. The numbers of the insects were so extraordinary that 
had they been vegetable feeders no living vegetation could have existed 
on the field; whereas, in point of fact, no damage to the vegetation 
whatever, such as would be produced by feeding upon the roots, could 
be observed. An examination of the contents of the alimentary canal 
also at once directly negatives the vegetable feeding habit. The food is 
obviously decaying vegetation—soilhumus. In view of the well-known 
habits of the group of Scarabzeidze, to which Allorhina belongs—namely, 
the Cetonians, all of the species of which, whose habits are known, 
being feeders upon decaying vegetation only, it seems strange that the 
root feeding hypothesis should ever have been adopted. Probably the 
basis of such an hypothesis was the great abundance of the larvze in 
the soil and their resemblance to Lachnosterna larve. 
That these larve may occasionally cut off a plant root, or that they 
may, as stated by Riley, when in confinement occasionally devour the 
roots of plants, is possible. They have reasonably strong jaws, and, as 
is well known, the normal habits of an insect are greatly altered in 
confinement. It is well known in Europe that the larvie of the cock- 
chafer (Melolontha vulgaris), which normally feed upon the roots of vege- 
tation, become carnivorous in confinement—the larger larvie- feeding 
upon the smaller ones. Similar observations have been repeatedly 
made with the Allorhina in the course of the rearing-cage experiments 
at the Department of Agriculture, and by Mr. R. 8. Lull, when engaged 
in work for this office at the Maryland Agricultural Experiment Station. 
Mr. Lull’s experiments show that under these conditions they not only 
feed upon one another, but also upon earthworms, which were placed 
in the jar for the purpose of this experiment. Professor Townsend also 
has recorded in the article above mentioned the feeding of the larve 
of Allorhina mutabilis upon an undetermined elongate white larva when 
left over night together in a tin can. 
Taking all these considerations together, it is probably safe to say 
that the normal food of the Allorhina larva is the vegetable mold of rich 
soils, and that in its larval stage it is not a crop pest. 
The length of life of the larva is unfortunately a matter of some 
doubt. It has been found impossible, in spite of repeated attempts, to 
