224 BOPYRTD^. 



whereas Gyge is only so at the anterior portion of the 

 animal. 



It also differs in the more rudimentary condition of 

 both pairs of antenna, and in the larger development of 

 the ovigerous plates. 



The male is in proportion much larger, being nearly one- 

 half the length of the female. It has also the cephalon 

 proportionately larger, and the antennas, particularly those 

 of the second pair, largely developed. The segments of 

 the pleon are distinct, anteriorly being nearly as large as 

 those of the pereion, and decreasing in length and breadth 

 posteriorly very rapidly ; whereas in Bopyrus they are 

 fused together except at the margins, smaller than those 

 of the pereion, and decrease gradually. 



The larvse of this genus appear to correspond very 

 closely with those of Bopyrus, but appear to have tiie 

 antennae laterally nearer to one another. 



