THE GENUS PERILESTES (ODONATA) 

 By E. B. Williamson and J. H. Williamson 



The genus Perilestes contains three hitherto described species to which six 

 are added in this paper. They are of similar general appearance and have 

 long slender abdomens and relatively short wings. They bear a striking 

 superficial resemblance to species of the protoneurine genus Protosticta of 

 the Oriental fauna. The obvious superficial difference is in the shape of the 

 apical segments of the female where Protosticta has the characteristic pro- 

 toneurine apical enlargement beginning at the apex of segment 6, while in 

 Perilestes 7 is only of normal size, and the great development in Perilestes 

 of segment 9 into an almost globular form does not occur in Protosticta, 

 though both have the segment relatively very large when compared with 

 the abbreviated eighth segment. 



The genus is characterized by the following venational characters : the 

 apical posterior angle of the quadrangle reaches the wing margin, M3 arises 

 at the first or between the first and second postnodals and Rs arises from the 

 fifth to the ninth postnodal. Kennedy has erected for the genus the sub- 

 family Perilestinae of the family Lestidae. It had been placed in the Legion 

 Podagrion by De Selys (Megapodagrioninae of more recent authors). The 

 genotype is fragilis Hagen as redescribed in this paper. 



Cteneric and Specific Characters 



In addition to the venational characters mentioned above, which make the 

 recognition of the genus an easy matter, the species have a number of other 

 characters in common. The dorsum and rear of the head are black, largely 

 shiniiig and with greenish or bronzy reflections. The thorax is dark striped 

 with pale, the sterna are black, and the abdomen is patterned in light and 

 dark colors, the most striking of which is a bright pale ventral area on the 

 apical segments of the male. The wings are hyaline with unicolored stigmas 

 and largely black venation. The legs are moderate in length, rather weak 

 and with a few relatively long spines. The two to five basal spines in the 

 ventro-anterior row of the first femur are modified similarly to those form- 

 ing the comb-like grouping of spines in the same row near the apex of the 

 first tibia. The superior male appendages are forcipate, and the inferior 

 appendages are rudimentary. In the female the valves of the ovipositor are 

 smooth along the ventral edge except at the extreme apex where each valve 

 terminates in two strong, nearly equal, ventrad directed teeth, these two 

 teeth in tandem, one anterior to the other. 



Specific differentials are given in the s^Tioptic key and in the descrip- 

 tions which follow. They may be briefly indicated. In Group II, probably 

 including the more primitive species of the genus, the venation is more 

 reduced than in species of Group I, as indicated especially by the origin 

 of Mia. In counting the cells behind Cuo we have used as the apical point 



