M Y S I D E A. 673 



have the first and second pairs of abdominal legs, as explained in our 

 remarks on the genus. 



In females, the sixth abdominal segment is entire below, without 

 teeth or spines, and with only the setules observed in the males. The 

 caudal segment is thin, without any protuberance or gibbosity below. 



In one male, about half grown, the anterior tooth of the sixth seg- 

 ment of the abdomen was obsolete, and the posterior spine was quite 

 short, although of the same general character as to its extremity as in 

 the full-grown males. This intermediate character in an immature 

 male seems to confirm our inference, drawn from the general identity 

 of character and their frequent association, that the animals described 

 as such are actually male and female. 



LUCIFER PACIFICUS. 



Segmentum antennale carapace paululo longius, utrinque antice acutum, 

 oculis paulo longius. Segmentum abdominis sextum dudbus preceden- 

 tibus simid sumtis parce longius et lamella caudali externd paululo 

 longius, infra integrum. iSeymentum caudale dimidio precedents bre- 

 vius, et dimidio lamellce externce paulo longius. 



Antennary segment slightly longer than thoracic, acute anteriorly on 

 each side. Anterior angles of thoracic segment bearing an acute 

 spine. Sixth abdominal segment a little longer than two preceding 

 together, and somewhat longer than the outer caudal lamella. Last 

 segment half shorter than preceding, and a little more than half the 

 length of the outer lamella. 



Plate 45, fig. 2, animal, enlarged. 



Pacific, latitude 15 20' south, longitude 148 west. Collected at 

 4 A. M., September 10, 1839. 



Length, three-tenths of an inch. Colourless. This species is near 

 the Reynaudii, but has not so long and slender a cephalic segment. 

 The eyes are clavate and somewhat longer than the part of the cephalo- 

 thorax, posterior to the antennary segment. The third of the five 

 pairs of legs, as usual, is much shorter than the second, fourth, or fifth 



169 



