40 



DIPTERA OF NORTH AMERICA. 



[PART III. 



in general, their plastic characters are so much alike that I can- 

 not point out any peculiarity, among the species I know of, which 

 might give rise to a generic subdivision. 



Next to Lamprogaster stands a genus of which Senopterina 

 decora Macq., from Tasmania, may be considered as the type; I 

 call it Euchalcota. The front is of about the same breadth as 

 in Lamprogaster, but is flatter and altogether furrowed-scrobi- 

 culate. The third antennal joint is still longer here ; the sharply 

 defined, deep antennal foveae are once and a half the length of 

 those of Lamprogaster, and reach almost altogether as far down 

 as the front part of the lateral edge of the mouth ; the arista is 

 beset with a short pubescence near its basis, otherwise bare ; 

 the clypeus is perceptibly narrower ; the occiput is less swollen, 

 so that the head is more closely applied to the thorax. The 

 latter is strongly built, but not as broad in the region of the 

 wings, and hence, of a more equal breadth; scutellum convex, 

 but not swollen, provided with six bristles. The venation is 

 similar to that of the preceding genera, but differs in the fourth 

 vein being gently curved forward before its eud, and in the third 

 vein being gently bent backward, so that the first posterior cell 

 is distinctly attenuated towards its end. The coloring of thorax 

 and abdomen is altogether metallic. In thus defining the char- 

 acters of the genus, I have taken in consideration some species 

 from Australia, which can very well be placed in the same genus 

 with the above named typical species ; nevertheless, they show 

 the following differences : the wings are comparatively longer 

 and without any picture, while in Euchalcota decora, the cross- 

 veins have dark borders alongside of them; there are no other 

 bristles in front of the row of bristles along the posterior part of 

 the thoracic dorsum, while in E. decora, there are some few 

 shorter and thinuer bristles immediately in front of that posterior 

 row. There is no necessity for a generic separation yet. I can- 

 not identify any of my species from Australia in a satisfactory 

 manner ; it may be that Chromatomyia laeta Walk, belongs 

 here. 



It would be difficult to explain why Macquart places Eu- 

 chalcota decora in his genus Senopterina. The structure of the 

 face and the shape of the thorax are entirely different. The 

 comparatively narrow abdomen of the male (I have not seen the 

 other sex) is almost the only point of resemblance. 



