ART. 11 CHRYSOTOXINE SYEPHID-FLIES SHANNOISr O 



E^ Third antennal joint much longer than basal ones com- 

 bined ; apical corners of tergites strongly projecting ; 

 very robust species. 

 F'. Second sternite with basal two-thirds yellow with a 

 dark median line extending back to post margin ; an- 

 tennae partly yellow draco, new species. 



F'. Second sternite black with yellow hind margins ; 



antennae wholly dark caeleste, new species. 



A'. Arista much shorter than combined length of first and second joints (fig. 



Ic), Palearctic species Subgenus Chrysotoxiim. 



B\ Only three yellow abdominal bands developed ; no distinct yellow spot 



above fore coxa bicinctum (Linnaeus). 



B^ At least four well-developed yellow stripes. 



C\ Abdominal side margins entirely black ; mark above fore coxa 

 present or absent; second sternite obscurely yellow basally. 



D\ Four anterior femora entirely yellow festivum (Linnaeus). 



D^ Four anterior femora black basally vernale Loew. 



C^ Abdominal side margins alternate black and yellow ; a distinct 

 yellow spot above fore coxa ; second sternite broadly yellow 

 basally. 

 D\ Wings without a distinct cloud near outer third on anterior 



margin elegans Loew. 



intermedium Meigen. 

 octomaculatum Curtis. 

 Dl Wings with a distinct cloud beyond middle near the costa. 



japonicum Matsumura ( ?) 



Primochrysotoxum, new subgenus 



Genotype. — Ghrysotoxum ypsilon Williston. 



This subgenus is differentiated from Ghrysotoxuvx^ sensu sfricfo, 

 by the relative lengths of the antennal joints. In Primochrysotoxum 

 the basal two antennal joints are but little elongated, and do not 

 exceed the length of the arista, (Fig. la and Ih.) In Ghrysotoxum, 

 sensu stncto, the two* basal joints are much longer than the arista. 

 (Fig. Ic.) 



GHRYSOTOXUM DERIYATUM Walker 



Ghrysotoxum derivatuni Walkee, List of Diptera, Brit. Mus., vol. 3, 1849, 

 p. 542. — CuRKAN, Can. Bnt., vol. 56, 1924, p. 110. — Johnson, Occ. 

 Papers Boston Soe. Nat. Hist., vol. 5, 1924, p. 97. 



This species has been recorded a number of times since it was first 

 made laiown. It is difficult to say how many of these records may be 

 correct; however, it is quite certain that small specimens of ventri- 

 oosum- (northwestern United States) are usually recorded as deri- 

 vatum. 



The Avriter has examined the type of derivatum and found it to be 

 difl'erent from all other species known to him. It is unusually small, 

 8 mm. The antenna and the fore tarsus are equal in length; the 

 relative length of the joints are 1:1: 2.5 ; the apical corners of the 



