108 
THIRTEENTH REPORT. 
RESULTS OF THE MERSHON EXPEDITION TO THE CHARITY 
ISLANDS, LAKE HURON. 
PRELIMINARY REPORT ON THE COLEOPTERA. 
A. W. ANDREWS. 
The writer spent eight days, June PI to 26, and July 16 to IT, 
on Charity Island, and one-half day, June 23, on Little Charity Island 
collecting Coleoptera for the Merslion Expedition.* Headquarters were 
established at the lighthouse on the larger island. 
Charity Island, where most of the work was done, is heavily wooded, 
and is in an almost virgin condition. The largest and most common 
trees are: Norway pine, Pinus resinosa Ait., red oak, Quercus rubra 
L., scarlet oak, Quercus coccinea Moencli., yellow oak, Quercus ellipsoid- 
alis E. J., white elm, TJlnms americana L., red maple, Acer rubruin L., 
sugar maple. Acer saccharuin Marsh, white birch. Betulcu alba />., cot- 
tonwood, Popu lus deltoides Marsh, and mixed with these, are medium 
and small trees of white pine, Pinus strobus L., common poplar, Populus 
tremuloides Michx. and others. A variety of trees and shrubs as bass- 
wood. Tilia americana, different species of willow and several species of 
dogwood grow on the edge of the woods bordering the shores. 
Charity Island proved to be very rich in Coleoptera. The collection 
has not been completely worked up, but it is estimated that about five 
hundred species and ten thousand specimens were collected in the short 
space of ten days. In this paper the writer has only attempted a gen- 
eral statement of the conditions. It is to be followed by a complete 
report when the material has all been worked up. 
One of the most striking facts about the distribution of the beetles 
on Charity Island was their great abundance on the northeast shore. 
During the June trip, two small gales from the northeast made collect- 
ing very good on this shore. The waves brought many insects to the 
beach, most of them alive and active, some dead and a few in a de- 
cayed condition, showing long immersion in the water. . 
The living beetles, as soon as they reached the sand or rocks, crawled 
up the beach. Some of these crawled upon boards and logs, many went 
underneath them and some made cells in the sand. Most of the species, 
however, remained thus sheltered for a number of hours and then dis- 
persed among the trees and shrubbery lining the shore. • 
The great number of insects in the waslmp attracted many species of 
beetles from the shrubbery, logs, etc., situated at some distance from the 
water. These beetles preyed on the living insects and fed on the dead 
ones on the beach. 
Various species of beetles were found in numbers running on the sand 
and rocks. The species Calosoma frigidum Kirby, was found in hun- 
*For a general account of this expedition see Rut liven, Alexander G., Science, N. S., XXXIII, pp. 
208 - 209 . 
