910 Charles Paul Alexander 



The genus Gnophomyia includes about twenty-eight species of medium- 

 sized to comparatively large flies, mostly from tropical America. The 

 immature stages so far as known are spent beneath the decaying bark 

 of deciduous trees (Liriodendron, Populus, Acer, and others). 



Gnophomyia tristissima O. S. 



1859 Gnophomyia tristissima 0. S. Proc. Acad. Nat. Sci. Phila., p. 224, pi. 4, fig. 18. 



Gnophomyia tristissima is a rather small blackish fly, with dark wings 

 and the knobs of the halteres bright yellow. The venation is as shown 

 in Plate XXXVII, 100. , , 



A second species of the genus, Gnophomyia luctuosa O. S. (Proc. 

 Acad. Nat. Sci. Phila., p. 224, 1859), has recently been taken near Wash- 

 ington, D. C, by Mr. Shannon. It is a southern species, with a wide 

 range over Central America and northern South America. It may be 

 readily distinguished from G. tristissima by its stouter build, entirely 

 black halteres, and apically pubescent wings. 



Genus Trimicra Osten Sacken 



1861 Trimicra 0. S. Proc. Acad. Nat. Sci. Phila., p. 290. 



The genus Trimicra includes about fourteen described species of rather 

 inconspicuously colored flies of medium size. The species are found 

 in all the principal regions of the globe, including many of the oceanic 

 islands. The genotype, Trimicra anomala, was later considered by its 

 describer as being the same as the European T. pilipes Fabr., but the 

 two should be regarded as being distinct species until the question can 

 be settled by the study of ample material. The immature stages are 

 spent in moist earth. 



Trimicra anomala O. S. 



1861 Trimicra anomala O. S. Proc. Acad. Nat. Sci. Phila., p. 290. 



Trimicra anomala is a brownish gray fly. The prescutum has three 

 dark brown stripes, and the abdominal segments are margined laterally 

 and caudally with paler. The wings (Plate XXXVII, 99) are suffused 

 with pale brown, the cross-veins being a little darker. The legs and the 

 body are clothed with long, erect hairs. The species is more numerous 

 southward and westward. 



