INJURIOUS liND BENEFICIAL INSECTS OF CALIFORNIA. 



349 



Host. — The cottony cushion scale (Icerya purchasi Mask.) is the 

 normal host of this insect, and while it is not as consistent and reliable 

 in its work upon the scale as are the ladybird beetles {Novius cardi- 

 nalis and N. koebelei), yet its w T ork is often phenomenal. During the 

 summer of 1912 Mr. A. S. Hoyt, Deputy State Quarantine Officer, 

 reared quantities of the Mies in Los Angeles County. 



THE WILD PARSNIP LEAF-MINER 



I'lu/loiu ii:ii albiceps Meigen 



(Fig. 34 6.) 



Description. — The flies arc exceedingly small, black or metallic-blue, 

 with the front and cheeks, bases of the wings, hands around the last 

 segment of the abdomen, 

 knees of the femora and the 

 tibiae yellow. The length is 

 about ; i\ inch. The puparia 

 are black with two noticeable 

 breathing tubes at one end. 



Life History. -The life 

 history of this species greatly 

 resembles that of the chrys- 

 anthemum leaf-miner, ex- 

 cept that the pupal stage is 

 not passed within the mines, 

 but in the soil. 



Nature of Work. — The 

 work greatly resembles that 

 of the chrysanthemum leaf- 

 miner. 



Distribution. — This fly is generally distributed throughout the State. 

 It was taken in large numbers in the San Francisco Bay region in 

 June, 1914, by the author. 



Food Plants. — The leaves of the giant wild parsnip are commonly 

 attacked in this State. 



Natural Enemy. — A majority of the puparia are parasitized by a 

 small black hymenopterous insect (Diaulinus begini Ashm.). 



Fig. 346. — Pupae and adults of the wild parsnip 

 leaf -miner, Phy to mysa albiceps Meigen. The three 

 specimens of Diaulinus begini Ashm. were reared 

 from the pupa?. Enlarged twice. (Original) 



THE CHRYSANTHEMUM LEAF-MINER 



Phytomyza chrysanthemi Kowarz 

 [Napomyza chrysanthemi (Kowarz)] 



(Fig. 347) 



Description. — The flies are very small, averaging about 2-25 inch 

 in length. The face is yellow; antennae, black; thorax and scutellum, 

 gray with a pale yellow stripe in front of the base of each wing; the 

 abdomen, black with ventral sides pale yellow, and the legs, black with 

 yellow markings. The maggots are light and very small. The puparia 

 are dark brown and locked within the mines in the leaves. 



