398 PROCEEDINGS OF THE NATIONAL MUSEUM vol. los 



the third and fourth at least two times as far apart as the second 

 and third (fig. 124). The usual arrangement is for the third dorso- 

 central to be opposite or only slightly anterior to the supraalar with 

 the third and fourth dorsocentrals about 1.5 times as far apart as 

 the second and third (figs. 101, 120). L. commelinae is the only 

 Liriomyza species known to me that has the third antennal segment 

 of the male enlarged (fig. 102). This characteristic is found in 

 all species of the subgenus Dizygomyza of Phytobia. Liriomyza 

 fumicosta has the costal margin of the wing infuscated (fig. 108). 

 Probably the most distinctive North American species that I have 

 seen is L. deceptiva. The genovertical plates are very prominent 

 and raised above the plane of the frontal vitta (fig. 104). Near the 

 lunule these plates widen to equal about one-third of the width of 

 the frons. The genovertical plates are proportionately broader for 

 their fuU length in species of Metopomyza (fig. 128). 



Besides the aforementioned sorosis group, three others, all within 

 the pusilla complex, may be designated. These are based primarily 

 on the colors of the vertex and genovertical plates (Frick, 1956a). 

 The first may be called the trifolii group (couplet 34) . Both vertical 

 setae are on yellow and there are two rows of acrostichals. The 

 second is the eupatorii group (couplet 29). Here the verticals arise 

 from black, the genovertical plates are yellow, and there are four 

 rows of acrostichals. The last group (couplet 27) contains pictella 

 and is named for it. The genovertical plates being infuscated separate 

 this group from that of eupatorii. The remaining species cannot be 

 placed into groups because of wide differences between them. 



Several species are herein deleted from the North American list. 

 These include L. pusilla (Meigen) and L. virgo (Zetterstedt), neither 

 of which I have seen in my studies. The South American Agromyza 

 xanthophora (Schiner) apparently belongs to Phytobia (Phytobia) and 

 may be the same as P. (Phytobia) picta. No type specimens of 

 A. xanthophora can be located. 



Key to the described species of Liriomyza 



1. Mesonotum with a prescutellar yellow rectangular or triangular area between 



the dorsocentral setae extending anteriorly at least to the fourth dorsocentral 



(figs. 99, 101) 2 



Mesonotum without such a prescutellar yellow area but sometimes with a 

 wide yellow crossband, centrally not extending to the fourth dorsocentral 

 (figs. 103, 109) 16 



2. Third antennal segment all or partially brown or black (figs. 115, 126) . . 3 

 Third antennal segment yellow 6 



3. Mesonotum subshining, not poUinose 4 



Mesonotum dull, gray pollinose 5 



