OF WASHINGTON. 505 



THE BLASTOPHAGA AT FRESNO, CAL., IN 1900. 



The winged female Blastophagas* commenced to emerge from 

 the winter figs on March 28, and continued to do so until the 

 end of April. The females at once enter the young figs of the 

 spring crop of the Caprifig trees. Under normal conditions the 

 ct outdoor" life of each individual female Blastophaga does not 

 last longer than 5 or 6 minutes ; it takes from 3 to 4 days, or from 

 5 to 8 days, according to the season, for the Blastophaga females 

 inhabiting an individual fig to issue from the same ; it takes about 

 5 weeks for one entire generation of Blastophaga to issue from 

 the figs in which they have developed ; the life duration of an 

 individual Blastophaga averages (excepting of course in the hiber 

 nating generation) 64 days. 



The first, or spring generation of Blastophaga issued from the 

 spring crop (Profichi) of male figs between June 1 1 and July 5. 

 It is well known that the female Blastophagas of this generation, 

 when issuing from the profichi figs are covered with pollen, and 

 that they can be used for caprification, i. <?., for pollinating the 

 blossoms of the female figs by transferring the male figs onto the 

 branches of the female tree.j 



The Blastophagas thus used are of course lost for the propaga 

 tion of the species, but those left on the male trees enter and ovi 

 posit in the succeeding generation of male figs which constitute 

 the first set of the second crop (fall crop) of the Caprifig tree. 

 This set of figs is, however, very slow to make its appearance so 

 that there is only here and there a young fig to be seen on the 

 Caprifig trees at the time when the bulk of the Blastophaga 

 females emerge from the spring figs. This break in the succes 

 sion of the crops of the Caprifig has been noted by all writers on 

 the subject, but no explanation of this singular phenomenon has 

 ever been offered. In his reports to Dr. L O. Howard the 

 writer has attempted to give an explanation which, in due time, 

 will be published by the Department of Agriculture. As a con 

 sequence of this break, an enormous reduction in the number of 

 specimens of the insect takes place normally in' the second gen 

 eration. At Fresno, in 1900, the number of Blastophaga females 

 which issued from the spring figs was roughly estimated to be 

 more than three millions of specimens (the inhabitants of about 

 20,000 figs) ; whereas, in spite of the utmost care in transferring 



*The reader should bear in mind that the Blastophaga never lives in 

 the female figs, and that it solely develops within the so-called "gall 

 flowers" of the male tree. 



t An account of this operation as practiced for the first time in America 

 is published by Dr. L. O. Howard, in the Yearbook of the U. S. Depart 

 ment of Agriculture, for the year 1900. 



