112 NEOTROPICAL PSELAPHIDAE 



same general form, but slightly wider than the eighth segment; club formed 

 of the tenth and eleventh segments, of which the eleventh is conspicuously 

 large: segment X bilaterally very asymmetrical, much longer and wider than 

 ninth, of a rounded-triangular shape, and very asymmetrically articulated on 

 the antero-mesial face of the ninth segment. Because of this asymmetrical 

 articulation, the ninth and eleventh segments are in contact laterally, but 

 widely separated mesially because of the wedge of the tenth segment; segment 

 XI as long as the second to the seventh inclusive, asymmetrically subconical, 

 with the apex acute, lateral face slightly and sinuately concave and the 

 mesial face convex. 



Melbamima clavicornis represents a divergent, specialized trend from 

 Melba, since most species of the latter genus have only slightly asymmetrical 

 tenth antennal segments, but certain species such as Melba clavata have this 

 segment much more asymmetrically formed. One species represents the genus 

 so far: 



clavicornis Raffray. 1909. Brazil. Genotype. 



TRIMIOSELLA (Raffray, 1898) 



This also is a monotypic, melbaform genus, erected to contain a species 

 formally placed in the then expanded Trimiopsis. Such a course was necessary 

 following the restriction of Melba to contain only those species in which the 

 lateral pronotal foveae were placed far down on the sides of the prothorax and 

 hence invisible from above. In Trimiosella the lateral pronotal foveae are 

 within the lateral pronotal margins and hence fully visible from above. Tenth 

 antennal segment lenticular, and not asymmetrical. Males with seven sternites, 

 females with six sternites, the seventh male sternite being the one-plate, non- 

 carinated type of pygidium common to the melbaforms as a group. 



anguina (Reitter). 1883. St. Thomas, Virgin Islands. Genotype. 



RAMELBIDA new genus 



This new genus is erected for Melba quadrijoveata Raffray (1904, p. 537). 

 Raffray (1898, 1904, 1908) restricted Melba to those species having the lateral 

 pronotal margins rounded, and the transverse subbasal sulcus continuing down 

 the sides of the prothorax, ending each side in a lateral fovea. Consequently 

 these lateral foveae lie in or near the prosternum, and are not visible from a 

 dorsal point of view. In 1898 Raffray erected Trimiosella for Trimiopsis 

 anguina Reitter, since the latter, although closely related to Melba, had lateral 

 pronotal foveae visible from above. Later, Raffray (1904) described quadri- 

 joveata as a species of Melba. This was a mistake, since the latter species has 

 the lateral pronotal foveae also visible from above, and in fact, is so shown 

 in a figure (fig. 8, p. 537, Raffray, 1904). 



Melba quadrijoveata may be a Trimiosella, but at present the described 

 structure seems to be too divergent for this genus, and Ramelbida is erected 

 to contain the melbaforms having: (1) eleven-segmented antennae, the sec- 



