IV. The Spinach-Leaf Maggot, or Miner. 



{Pegomyia vicina, Liutn.)* 

 Order Diptera; Family Antiiomyiid.e. 



A small, white maggot toMch mines the leaves of spinach, beets 

 and ''Lamb's quarter,'' or ''Pigweed;' causing them to have a 

 blistered appearance. The eggs, which are deposited by an oliva- 

 ceous, ash-colored fly, are white and are usually to be found on the 

 lower surface of the leaves. 



Historical. — This insect has been called '" The Beet leaf 

 Pegomyia" by Professor Howard. As it causes the most marked 

 injury to spinacli in this section of the State I take the liberty to 

 call it "The Spinach-leaf Maggot or Miner." It has some near 

 ve\^ti^Q?> {Chartophila betarum,Unt and Fhorbia floccosa,Me^de) 

 which also mine the leaves of beets. 



The first record that I atn able to find of Pegomyia vicina's being 

 known as injurious to beets, as well as the first description of the 



• Two other species of flies have been reared by Dr. Lintner from maggots found mining 

 the leaves of beet; one of which (Chartophila betarum) was a new species. The other 

 Phorbia floccosa. Prof Slingerland thinks is identical with the "Cabbage-root Maggot 

 (Phorbia brassic*). Whether either of the above species mine the leaves of sp.naeh or 

 Chenopodium I cannot say. Twentyflve specimens were bred from spmach. A^^en from 

 Chenopodium and five from beet leaves, none of which agree wuh srec.mens of Phorb.a 

 brassica. bred from root, of cabbage and turnip. Specimens reared from both spmach and 

 Chenopodium were sent to L. O. Howard, of the Division of Entomology, who pronouuced 



Te:rif rnridlbltTariation in the size of the flies bred from all three plants, but those 

 bred from Chenopodium are all smaller than those reared from .he beet and spmach leaves. 

 They vary in color from an olivaceous ash to a very dark ash color. In addition to the 

 characters given by Dr. Lintner. the following are noted: AH the males (20 specimens) 

 bred htve the anterior femora, excepting the apical third, dark ash to black AlUi.ugh the 

 variation in the .enation of male and female shown in Fig. 5 and o' is partially due to the 

 angle at which the wines were photographed, there is as much variation in the venatu n of 

 Afferent specimens of both males and females as figured by Dr. Lintner for the t.o genera 

 ^artopJa and Pegomyia, but in no case are all the legs black. In all the mal. spec.mens 

 S^sabdonien is darker col-.red than in the females. (As material reared m breeding jarsis 

 Lie to be consigned to the -'Cyanide bottle " before the mteguments are hardened orre 

 variation in color must be allowed for the difference in the density of the inte.ument of dlf- 

 ferent species.) 



40 



