360 PROCEEDINGS OF THE NATIONAL MUSEUAI vol. loe 



The genus Pialea was described by Erichson (1840) for his new 

 species lomata from Brazil. Westwood (1876) named a second species, 

 lutescens, also from Brazil, but questioned its placement in Pialea 

 because of the difference in the antennal insertion and slight dif- 

 ferences in wing venation. Brunetti (1912) established the third 

 species, aurijnla, from Burma, and (1920) a fourth species, jardinei, 

 from Ceylon. Thus, four species have been described from four 

 specimens of two different zoogeographical regions. 



Hunter (1901) and Kertesz (1909) listed lutescens as a synonym of 

 lomata in then- catalogs, and Brunetti (1912 p. 474) apparently fol- 

 lowed them without question. How Hunter came to synonymize 

 these species remains a mystery to me. Bezzi (1912, p. 78) attempted 

 to show that these two species were distinct, basing his evidence on 

 a male specimen from Brazil, which he determined as lomata. 



I have been able to study the female type of lomata, the male type 

 of auripila, and four other specunens representing the three new 

 species herein described. An examination of the type of auripila 

 revealed that it belongs to a new genus related to Astomella Lamarck. 

 Judging from Brunetti's description of jardinei, I believe the species 

 belongs to Astomella, rather than to the new genus to include auripila, 

 which will be described in a later work. This transfer now leaves 

 Pialea with only two known species, lomata and lutescens, both from 

 Brazil. 



Sexual Dimorphism 



Sexual dimorphism of Pialea species is readily apparent only in 

 the structure and insertion of the antennae, the longer wing length 

 of the female, and in color patterns as in ecuadorensis, new species. 

 Both color patterns and wing length are sexual differences occurring 

 throughout the family, but I am unaware of this great antennal 

 dimorphism in any other genus of Acroceridae and it may be con- 

 sidered unique for the family. The closely related genus, Stenopialea 

 Speiser (1920, p. 205), may share this trait, but as yet only the male 

 of its single species, beckeri Speiser, is known. 



The sexual antennal dimorphism that has been studied hi Pialea 

 may be summarized as follows: Females have their antennae attached 

 to the ventral surface of the antennal tubercle, and thus the antennae 

 point downward throughout their length; the base of the fu*st antennal 

 segment is at or below the mideye height level; the antennal tubercle 

 is typically smaller than in the males (fig. 3,a-c), and the first and 

 third antennal segments are shorter and more conical or rounded than 

 in the males. Males have their antennae attached to the anterior 

 surface of the antennal tubercle and only the terminal segment points 



