416 PROCEEDINGS OF THE NATIONAL MUSEUM vol. io8 



position of m-m and the presence or absence of the basal section of 

 M3+4 are the only characters that separate all species of Phyiogromyza 

 from Pseudonapomyza. In Pseudonapomyza, m-m is basal to r-m 

 and appears to be the basal section of M3+4 (fig. 135). There are 

 species in Phytagromyza that lack the orbital setulae and have only 

 one upper-orbital, one to five lower-orbitals, the third antennal seg- 

 ment as angulate as it is in Pseudonapomyza (fig. 136), two to seven 

 dorsocentrals, and the intraalar and prescutellar setae present or ab- 

 sent. The larvae of the type species, Phyiogromyza jiavocingulata 

 (Strobl), mine the leaves of grasses. The larvae of Pseudonapomyza 

 species mine exclusively in species of Gramineae. 



Phytagromyza and Pseudonapomyza are the only genera in the Phy- 

 tomyza group that have the orbital setulae erect or reclinate. The 

 group of genera closely related to Phytomyza has the costa ending at 

 R4+5, and Mi+2 is the weakest vein (figs. 134, 145). 



There are only five described species in North America, three of 

 which are Nearctic in distribution and two are Holarctic. There are 

 about 27 species described from the Palaearctic region. 



Key to the described species of Phytagromyza 



1. Crossvein m-m present (fig. 134) 2 



Crossvein m-m absent 4 



2. Mouthparts not elongate, in length less than the eye height (fig. 133); meso- 



notum dull black, grayish pollinose 3 



Mouthparts elongate, in length subequal to the eye height (fig. 131); meso- 

 notum shining dark brown nitida 



3. Head with two or three orbital setulae (fig. 133) ; notopleural triangle yellow. 



plagiata 

 Head with six or seven orbital setulae; notopleural triangle brown . lonicerae 



4. Veins R4.1-5 and M1+2 with wing tip between them; head, pleura, and legs mostl}' 



dark brown orbitalis 



Vein Mi+2 at wing tip; head, pleura, and legs yellow populicola 



Phytagromyza lonicerae (Robineau-Desvoidy) 



Phytomyza lonicerae Robineau-Desvoidy, Rev. Mag. Zool., ser. 2, vol. 3, p. 396, 



1851. 

 Phytagromyza lonicerae (Robineau-Desvoidy), Hering, Notulae Ent., vol. 31, p. 



36, 1951 (figures of larv'al and puparial characters). 



This dark Holarctic species has the mesonotum dull black and gray- 

 ish pollinose and the notopleural triangle dark brown. There are 

 about six developed dorsocentral setae, the head is dark except for the 

 yellow dorsal half of the frontal vitta, and the eye is about four-fifths 

 as long as high. The larvae form very wide serpentine mines in the 

 leaves of Lonicera involucrata Banks and Symphoricarpos albus (L.) 

 Blake. The larvae appear early in the spring and there is only one 

 generation a year. I have seen no specimens other than mj reared 

 series from central California. 



