June, '07] ENTOMOLOGICAL NEWS. 263 



known as belts. The life zones are divided into the following: 



The sub-tropical comprising a small portion of the Colorado 

 river; the Lower Sonoran, the desert area, characterized, by 

 the creosote bush, tree yuccas, cactii and sand bur ; the Upper 

 Sonoran, or chaparral zone characterized by ceonothus, man- 

 zanita and different scrub oaks ; transition zone or yellow pine 

 belt. In this zone there are two centres of origin, the northern 

 and southern. The mixing of these two origins determined the 

 name of this zone. Above this is the timber belt. Mr. Hall 

 considers this as one zone, but Dr. Merriman subdivides it into 

 the Hudsonian and Canadian zones. Alpine hemlock, white 

 bark pine, little sugar pine are found here. The Alpine zone 

 characterized by Alpine sorrel. 



The zones can be mapped out, but the reason and cause of 

 the zones have yet to be determined. 



Mr. J. S. Hunter, who has charge of the mosquito extermina- 

 tion work at San Mateo and Burlingame, then gave an outline 

 of the work that has been done. He dwelt at length on the 

 importance of the mosquito problem. The work of extemina- 

 ting the mosquito was first undertaken about four or five years 

 ago at San Rafael, under the direction of Mr. Ashman. About 

 three years ago the Burlingame Country Club asked for help in 

 the mosquito problem, as they were exceedingly troublesome. 

 The two species that are most troublesome are the salt water 

 forms, the Culex lattivittatus and Culex squamiger. These are 

 more difficult to control than the fresh water forms on account 

 of the great extent of the marshy land and direction of the 

 winds from South San Francisco. In conclusion Mr. Hunter 

 said the work is still in continuance and it is hoped that this 

 region in time may be fully freed of these insects. 



Mr. Ehrhorn and Mr. Van Dine were unanimously elected 

 members of the club. 



Adjournment and refreshments followed. 



Julia D. E. Wright, Secretary. 



The regular meeting of the Santa Clara Valley Entomological 

 Club was held last Friday night, March 8th, at the Delta 

 Upsilon House, Stanford University. 



