438 PROCEE.DiINGS OF THE NATIONAL MUSEUM vol.94 



The three species inckided in this genus have in common the simple, 

 rather slender tergal processes of the terminalia; the short, simple, 

 truncate process of the hypandrium ; and the two-segmented left cercus 

 with the basal segment inwardh^ lobed and echinulate. M. aequalis is 

 only tentatively assigned to the genus. It probably is generically 

 distinct, but a final conclusion must await further data. 



KEY TO SPECIES OF MESEMBIA (MALES) 



1. Left cercus with echinulate lobe located medially on inner side of basal seg- 



ment ; Cuba hospes 



Left cercus with echinulate lobe located distally on inner side of basal seg- 

 ment 2 



2. Left tergal process very slender, abruptly directed mesad; tenth tergal cleft 



attaining base; Haiti haitiana 



Left tergal process as broad as or broader than the right process, slightly 

 curved outward ; tenth tergal cleft terminated just wilhin basal half : 

 southern Brazil aequalis 



MESEMBIA AEQUALIS. ne-.v species 



Figures 64-66 



Male. — Color (in alcohol) : Head and antennae black; legs, ptero- 

 thorax, abdominal terminalia, and dorsal maculation mahogany 

 brown ; prothorax with yellowish intersclerotal areas, sclerites brown. 

 Length 6.7 mm. ; forewing length 4.0 mm. ; breadth 1.0 mm. 



Head (fig. 64) with eyes medium sized, scarcely inflated, separated 

 by an interspace 3 eye widths wide ; sides behind eyes ll^ eye lengths 

 long, nearly straight, gradually convergent; caudal margin abrupt, 

 obtusely rounded. Mandibles small, sharply pointed; left mandible 

 with inner margin biemarginate, the right with inner margin evenly 

 arcuate. Occipital foramen rounded anteriorly. Antennae darkly 

 pigmented throughout, l7-segmented (broken). 



Figures 64—66. — Mesevibia aequalis, new species, holoiype male (Brazil): 64, Head; 65, 

 terminalia (dorsal); 66, terminalia (ventral). Explanation of symbols on p. 403. 



