378 PROCEEDINGS OF THE NATIONAL MUSEUM vol. los 



partially brown or black. One North American species, Phytobia 

 maculosa, is atypical; the characters it has in common with Phytobia 

 were discussed by Frick (1952). The larvae have three bulbs on 

 each posterior spiracle, none of which are elongate or modified. 



Key to the described species of Phytobia (Amauromyza) 



1. Halter dark brown; mesonotum dull brown abnormalis 



Halter black with a white spot on knob; mesonotum shining black . maculosa 



Phytobia {Amauromyza) abnormalis (Malloch) 



Agromyza abnormalis Malloch, Ann. Ent. Soc. Amer., vol. 6, p. 320, 1913 (figure 



of wing) . 

 Dizygomyza {Amauromyza) abnormalis (Malloch), Hendel, in Lindner, Die 



Fliegen der palaearktischen Region, fam. 59, p. 59, 1931 (figures of head 



and wing) . 



This Holarctic species is completely dull brown to black with the 

 halter, wing base, and calypter dark. Even the wing is not clear, 

 but has a gray to brownish tinge. The larvae mine the stems of 

 Amaranthus spp. and Chenopodium album L. I have seen specimens 

 from Kansas, Iowa, and District of Columbia. 



Phytobia {Amauromyza) maculosa (Malloch) 



Agromyza maculosa Malloch, Ann. Ent. Soc. Amer., vol. 6, p. 302, 1913. 



Unique among North American Phytobia species in having a black 

 spot on the knob of the halter. Frick (1952) discussed the subgeneric 

 position of this species and listed four host plants. Other larval hosts 

 include Chrysanthemum spp., Bidens pilosa L., Helianthus annuus L., 

 and Lactuca sativa, cultivated var. The larvae form lai^e blotch 

 mines. The species is widespread in the United States and is also 

 known from Bermuda, Jamaica, Puerto Kico, Uruguay, Argentina, 

 and Hawaii. 



5d. Subgenus Cephalomyza Hendel 



Cephalomyza Hendel, in Lindner, Die Fliegen der palaearktischen Region, fam. 

 59, p. 32, 1931. 



This subgenus is an odd and diverse group that has the frontal vitta, 

 antenna, and mesofacial plate primarily yellow, either has one upper- 

 orbital or has two with only one upper-orbital reclinate, gena pos- 

 teriorly about one-half the eye height, genovertical plates extendiag 

 beyond the eye margin (fig. 66), an epistoma present between the 

 subcranial margin and the mesofacial plate, and the legs primarily 

 dark. The larvae of one European species is known and each pos- 

 terior spiracle bears about nine bulbs. 



