October, '16] ESSIG: CHRYSANTHEMUM GALL-MIDGE 461 



this time Bordeaux is used at the rate of 4^-50; and Hme-sulphur at 

 the rate of 1-50. In the case of the apple and pear, arsenate of lead 

 may be added at the rate of 3 lbs. to 50 gallons of lime-sulphur in the 

 "pink" for apple scab, Venturia poini. The arsenate of lead incor- 

 porated against the codling moth will be sufficient in subsequent 

 sprays for the apple and pear. 



Explanation of Plates 32, 33 



1. Cherries pitted and deformed by Syneta albida Lee. 



2. Young cherries pitted and stems gnawed, adults. 



3. Apple showing the characteristic work of the adults on foliage. 



4. Injured and uninjured apple blossoms. 



Chairman H. J. Quayle: The next paper will be by E. 0. Essig on 

 the chrysanthemum gall-fly. 



THE CHRYSANTHEMUM GALL-FLY, DIARTHRONOMYIA 

 HYPOG^A (F. LOW) 



Cecidomyia hypogcea F. Low, Verh. Zool.-Bot. Ges. Wien, XXXV, 

 p. 488, 1885. (Figures 1-7) 



By E. O. Essig, Agricultural Experiment Station, Berkeley, California 



Though the chrysanthemum gall-fly has been known as a pest in 

 Europe for many years it was not recorded as occurring in the United 

 States until April 1915 when Dr. E. P. Felt received specimens from 

 Prof. R. H. Pettit of Michigan.^ In September of the same year Mr. 

 C. C. Barnum, a student at the University of California, called atten- 

 tion to the work of a gall-fly on chrysanthemums growing in a green- 

 house on the campus. From the infested plants the writer reared a 

 large number of adults, some of which were forwarded to Dr. Felt who 

 kindly determined them as the above and gave the published records 

 of its previous occurrence in this country. Since that time the writer 

 has made a general survey of the central part of the state and has 

 found that the insect is quite abundant and destructive in the region of 

 San Francisco Bay. 



Description 



The larvae or maggots (Fig. 32 B) are very small, averaging only about 1.5 mm. in 

 length and 0.8 mm. in diameter when fuU-grown. The shape is somewhat cylin- 

 drical with the anterior end more or less pointed and the posterior end broadly 

 rounded. The color varies from transparent-white to pale yellow or orange. 



1 Jr. Econ. Ent. VIII, p. 267, AprU 1915. 



