RESULTS OF THE MERSHON EXPEDITION TO THE CHARITY 

 ISLANDS, LAKE HURON: COLEOPTERA. 



A. W. ANDREWS. 



The Avriter was a member of the Mcrshon Exi)e(litioii of the University 

 of Michigan for nine days in 1910. He was on the islands from June 

 19 to June 26 and on July 16 and 17. During this time the beetk; 

 fauna was studied carefully with the result tiiat 623 species were ob- 

 tained with habitat data^ The field work covered such a short period 

 that much remains to be done, but contUtions were so favorable and the 

 results form such a considerable contribution to our knowledge of the 

 fauna of these islands that it seems best to pu])lish them. 



The location and description of the Charities have been given b\- 

 several men. Briefly, they consist of three small islantls in the mouth 

 of Saginaw Bay, and are distant about ten and eight miles from the 

 south and north shores, respectively. Gull Island is the smallest of the 

 group, and was not studied. Little Charity is second in size and has 

 some forest cover. It was apparently poor in Coleoptera and received 

 little attention. Charity Island^ the largest in the group, contains 

 about 650 acres, is densely wooded in the interior, supports a pond of 

 a})out 2 acres, has extensive sand and rock beaches, and has l)een 

 practically undisturbed by man It was found to be very ricli in 

 beetles and received practically all of the writer's attention. 



HABITAT DISTRIBUTION OF THE COLEOFTERA. 



The northeast beach <^f Charity Island provetl to be the most im- 

 portant beetle habitat. A great numl)er of specimens were found on 

 the logs, rocks, stones, and sand, and on the bushes wdiich are here l)ut 

 a few yards from the water's edge. At the time studied tlu> conditions 

 favored the concentration of beetles on this shore. The wind blew 

 steadily for twelve out of fourteen days from the northeast, and the 

 waves washed up specimens of various species and a considerable 

 amount of food that attracted carnivorous s])ecies. Other sjiecies were 

 obtained by beating the bushes and trees, on the toj) and under boards 



' The writer is indebted to John D, Sherman, Jr., Brooklyn, X. V., for the determination of 

 many species of Caral)idae and Dytiscidae; to A. B. Woleott of the Fiel<l Museum of Natural 

 History, Ciiicago for namiii}? many species of (^nrculionidae and lOlateridae, and to K. K. 

 Swartz of the \J. S. National Museum for a luimberof si)eeies of C'nreulionidae an<l I'Materidae. 

 He is also indebted to Captain Cliarles McDonald and his a.ss'stant, Josepii .Singleton, of the 

 lighthouse of Charity Island, for assistance in the field. 



