188 DIPTERA OF NORTH AMERICA. 



joint, which is not black. Foisers yellowish, the base of the knob 

 blackish. Wings yellowish, appearing almost golden yellow in an 

 oblique direction, with bright spots of a violet reflection. Before 

 the second longitudinal vein there are two such spots, the first 

 immediately beyond the tip of the first longitudinal vein, the 

 second between the first and the tip of the second longitudinal 

 vein. Between the second and third longitudinal veins there arc 

 three violet spots, the first of which is the largest ; it is situated 

 under the first costal spot and runs far towards the base of the 

 wing in the form of a wedge without sharp limitation ; the second 

 is the smallest, and is placed below the yellowish space between 

 the two costal spots ; the third is a double spot almost S shaped, 

 and united to the second costal spot with its anterior end. Behind 

 the third longitudinal vein the violet color prevails to such an 

 extent as to leave only two golden spots, one of which is placed 

 behind the anterior branch and the other immediately behind the 

 posterior branch of the third longitudinal vejn. The cilia of the 

 wings are quite pale yellowish, but blackish where the violet spots 

 reach the margin of the wing. 



Hub. Washington. (Osten-Sacken.) 



This species resembles very much the European Diplosis yavo- 

 nina Loew, but is easily distinguished from it by the smaller ex- 

 tent of the violet color of the wings, the smaller extent of the 

 black color of the legs, and the sharper limitation of both colors. 

 "Whether the male of Diplosis pavonina has likewise the joints of 

 the antenna} alternately dark-colored I do not know, as I did not 

 succeed in discovering it ; judging, however, by the appearance 

 of the antennae of the female, this does not seem to be the case." 



II. Galls or larva} known, perfect insect unknown. (The descrip- 

 tion of these galls and larva? is given below, under the indi- 

 cated numbers.) 



On hickories, Carya, of different kinds, seven species, besides one belonging 



to the third category. (Nos. 1 — 8.) 

 On the golden-rod, Solidago, of different kinds, two species, besides other 



two belonging to the third category. (Nos. 9 — 12.) 

 On Vaceinium (or Gai/Iitsvnia /), one species. (No. 13.) 

 On the Bomb pine (Pimm tnopt), two species. (Nos. 14 and 15.) 

 On the red maple [Acer wortim), one species. (No. 17.) 

 On tli«' ash (Fraxinua omericana), one species. (No. 18.) 

 On the oaks of different kinds (QuercuOi fotw species. (Nos. 19 — 22.) 



