E. T. CRESSON, JR. 49 



Hydrellia hypoleuca Loew 



1862. Hydrellia hypoleuca Loew, Mon. Dipt. N. Am., i, 1.51. 

 1862. Hydrellia scapularis Loew, Mon. Dipt. N. Am., i, 152. 



I cannot separate the Costa Rican specimens specifically from 

 those found in the United States. The species is very variable, 

 and probably is a variety of the European griseola. The color 

 of the face ranges from white to yellow or golden, and perhaps 

 specimens will be found with it nearly black, as in variety obscur- 

 iceps Loew. 



The above synonymy is suggested and is probably correct. 

 The form with yellow face has been described as scapularis. 



The species is represented by seven specimens: Over mud at 

 Cartago, INIay 17, July 4, and November 21 ; Laguna del Dirumbo, 

 southern slope of Irazu, July 1.3. 



NOSTIMA 



1900. Coquillett, Can. Ent., xxxii, 35. 



Closely allied to Philygria, if not congeneric. The only constant 

 character I can find is the presence of but two pair of dorso- 

 centrals, and generally the arista has long hairs above. 



Two species are known from Costa Rica, and may be separated 

 as follows: 



Wings hyaline; legs entirely pale iminaculata 



Wings blackish, marked with numerous rounded white spots; legs spotted. 



slossonae 



Xostitna slossonae Coquillett PL III, fig. 15. 



1900. Nostima slossonae Coquillett, Can. Ent., xxxii, 35, (Florida). 



1914 Philygria calverti Cresson, Ent. News, xxv, 274, pi. x, f. 2, (Costa Rica). 



This is the prettiest species of the genus, and cannot be mis- 

 taken when once seen. The conspicuously marked wings and 

 the gray spotted mcsonotum and abdomen are very character- 

 istic. 



Represented by two specimens: Alajuela, September 15, and 

 Juan Villas, April 28 (at l)rook near woods). 



Nostima immaculata new species 



This species may be easily distinguished by the opaque, immac- 

 ulate frons and mesonotum, shining abdomen and immaculate 

 wings. 



TRANS. AM. ENT. SOC, XLIV. 

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