E. T. CRESSON, JR. 65 



Type. — cf ; Cartago, Costa Rica, February 19, 1910, (sweeping 

 over mud), [Type No. 6138]. Paratypes. — 3 cf , 2 9 ; topotypical. 



Also represented by a homotypical series of nineteen specimens 

 collected over mud: Cartago, December 12, 1909 to Maj' 17; 

 Southern slope of Irazu, near Cartago, December 15; Rio de las 

 Canas, near Santa Cruz, January 30; San Isidro, August 21; 

 Toyogres brook near Tierra Blanca, April 6. 



OCHTHERA 



1802. Latreille, Hist. Nat. Crust. Iiis., iii, 462. 



The species of this genus are easily recognized by the enlarge- 

 ment of the fore femora, which are greatl}^ dilated and flattened 

 as shown in figure. Only one species is known to occiu- in Costa 

 Rica, but no doubt others will be found. 



Ochthera hiunilis Williston PI. Ill, fig. 25. 



1897. Ochthera humilis Williston, Kans. Univ. Quart., vi, 6. 



Originally described from South America, and easily recognized 

 by the broad, golden yellow face, bearing the shining black tuber- 

 cle, and the metallic bronze mesonotal stripes. 



One specimen collected over grass muddy road at Peralta, 

 March 24. 



PLANINASUS 

 1914. Cresson, Ent. News, xxv, 245. 



I have not included this genus in the table, as it is probably not 

 an Ephydrid, but possesses many ephydrid characters and is 

 therefore noted here. The preapical tibial bristles are well devel- 

 oped, as well as are the second basal and anal cells. The dorso- 

 central bristles are in the same scries with the prescutellars, and 

 there are two distinct sternopleural bristles. The figure of the 

 head given will heli) one to recognize the genus. Only the fol- 

 lowing species is known. 



Planinasus ambiguus Cresson PI. Ill, fig. 28, 29. 

 1914. Planinasus atnbiguus Cresson, Ent. News, xxv, 246, pi. x, f. 5 to 7. 



Shining black; lunular area, halteres, coxae, basal half of all femora, bases of 

 fore and hind tarsi, yellow; lower part of the oblique facial plate metallic 

 tinged; lower part of face, when seen from above, pale metallic green. ^^ ings 

 brownish hyaline, immaculate. Length. — 3 mm. 



Described from a male collected in the \'alley of Rio Xaranjo, 

 Cachi, March 9. 



TRANS. AM. ENT. SOC, XLIV. 



