54 THE CANADIAN ENTOMOLOGIST. 



THE BEES OF THE CORONADO ISLANDS. 



BY T. D. A. COCKERELL, BOULDER, COLORADO. 



Out in the Pacific, on the edge of the continental shelf, south- 

 west of San Diego, California, are the Coronado Islands. They 

 consist of four rocky elevations, submerged mountain-tops ap- 

 parently; the largest, South Island, about two miles long. The\' 

 belong to Lower California, and hence are part of Mexico. Formerly 

 they were difficult of access, but now a small vessel makes daih 

 trips from San Diego, and tourists visit the islands in numbers. 

 On August 21, 1915, my wife and I spent two hours on South 

 Island, collecting the hitherto unrecorded insect-fauna, and especi- 

 ally the bees.* 



Such isolated spots arc extremely interesting to the exulution- 

 ist. Their fauna and llora may throw light on the rate of modifica- 

 tion of species, or they may preserve formerly widespread, but now 

 nearly extinct, types. The vertebrates of the Coronados have 

 already been rather carefully studied. They possess a mouse, 

 Peromyscus maniculatus diibius Allen, which occurs elsewhere only 

 on Todos Santos Islands, Lower California. It is a relatively 

 large, dark form. The birds, 22 species, have been fully discussed 

 in a very interesting paper by J. Grinnell and F. S. Daggett in 

 The Auk, XX, 1903, pp. 27-37. One of them, Melospiza corona- 

 torum, is peculiar to the islands, differing from its mainland relative 

 by its much paler ground colour, narrower streaking and smaller 

 bill. Another, Carpodacus dementis, agrees with a San Clemente I. 

 form, and differs from that of the mainland by the bulky bill and 

 heavy brown streaking. Thus it appears that the modification, 

 when there is any, may be in cjuite opposite directions. Nine species 

 of reptiles are recorded by Van Denburgh and Slevin, the most 

 interesting being Gerrhonotus scincicauda ignavus, which belongs 

 otherwise to the islands northward, Catalina and San Martin. 

 The plants have been little studied, but a fine Malvaceous species. 



*Dr. E. P. Van Duzee, in his account of the Hemiptera of San Diego and vicin- 

 ity, appears to record species from North Island Coronado but as his preface 

 shows, they came from the north end of Coronado Beach, San Diego, locally 

 called North Island. There is a possible source of confusion here, to be guarded 

 against. 



Februari', 19 IG 



