52 COSTA RICAN DIPTERA 



The species was originally" described from St. Vincent, West 

 Indies. It is here represented by a good series of sixteen speci- 

 mens, collected on the muddy beach of Rio Tempisque, Filadelfia, 

 January 18. 



Ilythea obscura new species 



Similar to flavipes but more opaque; the yellowish dust being denser, and the 

 abdomen subopaque, olivaceous and dusted with brown; not polished and jet 

 black. The wing maculation is the same as in that species. 



Type. — d^; Filadelfia, Costa Rica, January 18, 1910, (muddy 

 beach of Rio Tempisque), [Type No. 6125]. Paratopes. — 2cf , 

 topotypical. 



Also a male belonging here, from Banana River, November 9. 



PSILOPA 



1823. Fallen, Dipt. Suec, Hydrom., 6. 



The species of this genus are mostly shining black, rarely pale 

 in color, destitute of dense pruinose vesture. The face is evenly 

 convex, retreating below, rarely and only weakly foveolate, with 

 only one facial bristle. Antennae with strongly developed spine 

 on second joint, and third usually distinctly longer than broad. 

 Mesonotum with setulae arranged in well defined rows, and no 

 dorsal bristles except the usual prescutellar pair. 



The species should not be confused with those of Ochtheroidea 

 and other allies near Discocerina. They may, however, be some- 

 what difficult to separate from those of the closer allied genera, as 

 Clasiopella and Typopsilopa. Of the genus Psilopa, as here re- 

 stricted, there are only two species known from Costa Rica, but 

 no doubt others occur there. These two may be separated as 

 follows : 



Fore coxae, middle and hind tibiae, pale, fore femora black; face narrow and 

 transversely wrinkled willistoni 



Fore coxae and all femora and tibiae black; face broad and highly polished. 



meridionalis 



Psilopa meridionalis new species 



Black; antennae except apices of third joint, knees, apices of tibiae and 

 basal joints of tarsi, pale. Wings yellowish or whitish, blackened at extreme 

 base, iridescent, with j^ellow veins. 



Shining, more or less metallic tinged. Face higlily polished, evenly convex, 

 with bristles below middle of profile. Mesonotum faintly sculptured. Second 

 and third costal sections subequal. Length. — 2.8 to 3 mm. 



