E. T. CRESSON, JR. 45 



Table of Costa Rican Species 



1. Pleura and venter more or less cinereous, contrasting with the dorsum; face 



large, swollen and prominent 2 



The entire thorax and venter, dark, unicolorous; face less prominent. 



Opaque species decipiens 



Shining species obscura 



2. Second antennal joint with a flattened, mostly silvery, area above at apex . . 3 

 Second joint normal, without such area 4 



3. Frons horizontal; face dark puncticornis 



Frons convex; face white argyrostoma 



4. Fore femora of males more or less constricted beneath on apical thu-d, and 



with a mesal series of curved, flattened bristles ; females with face seri- 

 ceous, light in color ciliata 



Fore femora normal; face gray to brown 5 



5. Face, except foveae and parafacials, entirely dark brown. . . .brunneiceps 

 Face mostly cinereous or yellowish brown meridionalis 



Paraliinna (Phaiosterna) decipiens Loew 



1878. Paralimna decipiens Loew, Zeit. f. Ges. Naturf., 1878, 195, [Texas]. 



1916. Phaiosterna decipiens Cresson, Tr. Amer. Ent. Soc., xlii, 108. 



This and the following form constitute a group, which I have 

 given the subgeneric name of Phaiosterna. They are separated 

 from the other species by the absence of any decided gray or 

 white dusting. The abdominal segments may have olivaceous 

 tinged bands, but no other parts are so marked, at least not 

 with gray or white. 



In this species the variation in the amount of opacity or pruin- 

 osity, and in the color of the same, ranges from dark brown to 

 golden brown. The light abdominal bands are sometimes so 

 broad that they occupy the entire segment. Abraded specimens 

 may have the thorax shining, so that there is some danger in con- 

 fusing these with the next species, therefore care should be used 

 in determining such material. 



The species is well distril)utcd in Neotropical North America. 



Sixteen specimens were collected from the following localities: 

 Muddy bank of Rio Tempisque, Filadelfia, January 18; Santa 

 Cruz, Rio de la Cafias, January 30; Along ditch in Cartago, May 

 25 and July 4. 



Paralimna (Phaiosterna) obscura \\'illi8ton 



1896. Paralimna obscura Williston, Tr. Ent. Soc. London, 1896, 391, [St. 



Vincent]. 

 1916. Phaiosterna obscura Cresson, Tr. Ent. Am. Ent. Soc, xlii, 109. 



TR.\NS. AM. ENT. SOC, XLIV. 



