64 U.S. NATIONAL MUSEUM BULLETIN 244 



Male genitalia. — Apex of tegumen rounded, entire. Valves 

 broad, pulvilli well developed, partially covered with minute spines; 

 apex of sacculus with small spines. Vinculum with lower angles 

 often folded, thus much darker than remainder of sclerite; sloping 

 either abruptly or gradually to saccus. Aedeagus simple, without 

 basal dilation. Eighth sternite with undivided basal portion broad; 

 furcal arms divergent, short, stout. 



Female. — Unknown. 



Discussion. — One of the important, but by no means unique, 

 features of this new genus is the presence of an epiphysis on the fore- 

 tibia. This character thus has been emphasized in the formation 

 of the generic name "Lumacra" (leg with a thorn). 



It is possible to divide this genus into two groups based essentially 

 on the male genitalia and the eighth abdominal sternite. The lack 

 of correlation of other characters prevents me from giving these two 

 groups subgeneric ranking. They are presented merely to emphasize 

 certain fundamental relationships. 



Key to the Species of Lumacra 



la. Vinculum of male genitalia gradually tapering to indistinct saccus; lower 

 angles not darkened (fig. 261). 



"quadridentata" group 



2a. Forewings with apical third largely devoid of scales, semitransparent 



(fig. 19) 20. L. hyalinacra 



2b. Forewings uniformly scaled 19. L. quadridentata 



lb. Vinculum abruptly narrowing to distinct, rodlike saccus; lower angles 

 conspicuously darkened (fig. 258). 



"brasiliensis" group 



3a. Base of medius prominently divided within cell of both wings. 



16. L. brasiliensis 

 3b. Base of medius undivided in cell of forewing, but occasionally divided for 

 short distance in secondaries. 

 4a. Sc + Ri and Rs converging briefly beyond cell in secondaries; intercalary 



cells absent 18. L. haitiensis 



4b. Sc + Ri and Rs parallel beyond cell; intercalary cell sometimes present 

 in hindwing 17. L. kiinckelii 



THE "brasiliensis" GROUP 



Included in this group are the species Lumacra brasiliensis, L. 

 haitiensis, and L. kiinckelii, which possess genitalia that are nearly 

 identical but which diverge from each other in certain minor features 

 of the wing venation. 



Male genitalia. — Vinculum %vith lower angles folded, appearing 

 quite dark; abruptly constricted to form rodlike, moderately long 



