E. T. CRESSOX, JR. 53 



Type. — cf ; Cartago, Costa Rica, May 17, 1909, (along ditch), 

 [Type No. 6126]. Parahjpes. — 3 cf , 1 9 , topotypical. 



Six specimens were also collected from the following localities: 

 Cartago, July 4; Laguna de Ochomogo, El Alto, July 4; Near 

 brook Toyogres, southern slope of Irazii, April 6. 



This species is probably the neotropical representative, or a 

 subspecies, of the northern aeneonigra Lw. 



Psilopa willistoni new name 



1896. PsiZopa njgrnmana WiUiston, Tr. Ent. Soc. London, 1896, 393 [nee Noti- 

 phila (Ephygrobia) nigrimana v. Ros., 1861]. 



This species belongs to a group comprising species which have 

 the fore tarsi somewhat dilated and always black; the face is 

 narrow, transversely convex and more or less rugulose, with the 

 bristles situated near the middle of the profile. The present 

 species is recognized l)}^ the j^ellow fore coxae, black femora and 

 immaculate wings. 



Two specimens were collected on the muddy beach of Rio 

 Tempisque at Filadelfia, January 18. 



The synonymy of nigrimana is possible on account of the synon- 

 ymy of the genera Psilopa and Ephygrohia. This situation neces- 

 sitated the creation of a new name for Williston's species. 



TYPOPSILOPA 



1916. Cre.sson, Ent. News, xxvii, 147. 



Allied to Psilopa, but with two i)airs of well deveIo|)ed dorso- 

 central bristles, exclusive of the usual prescutellar pair. 

 Typopsilopa flavitarsis Cresson PI. Ill, fig. 7. 

 1916. Typojmlopa flui'itarsis Cresson, Ent. News, xxvii, 147, (Arizona). 



Very similar to Psilopa atra Loew of the United States which 

 belongs to this genus, but the frons is very much obscured, caus- 

 ing the frontalia to be less distinct; the face is longer, more 

 obscured and wrinkled with the bristles situated higher. All 

 tarsi are yellow. Length. — 3 mm. 



One specimen: Near pond at Peralta, July 7. 



PLAGIOPS new genus 



Belonging to the group Psilopini and closely related to Dis- 

 comyza, Clanoneurum and Peltopsilopa. It is recognized by the 

 oblique head with the smooth, ]^olishcd face, which is nearly 



TRANS. AM. ENT. SOC, XLIV. 



