FAMILY EPHYDRID.E — THE SHORE FLIES 351 



24. Front shining 27 



Front pollinose 25 



25. Face with longitudinal ridges below (59, 73) Rhysophora Cresson 



Face without ridges below 26 



26. Eyes longitudinally oval (34) Ditrichophora Cresson 



Eyes not regularly oval, widened below the middle and narrowing the 



face above (10, 56) ^Dis^cocerina Macquart 



27. Face carinate above (15) Athyroglossa Loew 



Face very gently convex above, without a distinct ridge 28 



28. Face and front on the same plane, flat, the face slightly convex be- 



low (46) Plagiops Cresson 



Face, front or both conspicuously convex 29 



29. Second and third antennal segments pendulous, the third more than 



twice as long- as wide 30 



Antennae not pendulous, the third segment not twice as long as wide 

 (39, 61) Psilopa Fallen 



30. Spine of second antennal segment long and strong (62). 



Clasiopella Cresson 

 Spine of second antennal segment fine (77) Ceropsilopa Cresson 



31. Oral opening small; eyes usually with distinct hair 32 



Oral opening large; eyes usually bare 43 



32. Anterior femora greatly enlarged, their tibiae ending in a spur 33 



Anterior femora not remarkably enlarged, their tibiae not ending in a 



spur 34 



33. Scutellum with four marginal bristles (see text figure). 



Ochthera Latreille 

 Scutellum with two marginal bristles (64) Stenochthera Hendel 



34. Arista pectinate 35 



Arista bare or pubescent 38 



35. Face and front polished 36 



Face and front thickly pollinose 37 



36. Sides of the face with deep punctures resulting in short, transverse 



ridges (3, 16, 65) ='Ochtheroidea Williston 



Sides of face without pits or wrinkles Ceropsilopa Cresson 



37. Acrostical hairs absent (36) Nostima Coquillett 



Acrostical hairs present Hydrellia Desvoidy 



38. Mesonotum with three pairs of dorsocentrals, a strong one near the 



inner end of the suture, another in front; four scutellars (2, 18). 



Hydrina Desvoidy 

 Mesonotum with at most one pair of strong dorsocentrals, rarely an 

 extremely weak second pair 39 



* Cresson. 1918, Trans-Amer. Ent. Soc. xliv. i)i). r,G, 60 (Costa Rica). 



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