142 Messrs. T. and A. Scott on some 



a single apical seta springs from the end of the first joint. 

 Mandibles stout, the biting part armed with short blunt- 

 pointed teeth, except at the lower angle, where there is a 

 moderately long conical tooth. The inner branches of the 

 first pair of swimming- feet are composed of two nearly equal 

 joints, and reach to about the middle of the second joint of 

 the outer branches ; they are also furnished with two short 

 spiniform apical seta ; tiie first joint of the outer branches 

 is somewhat longer and the second joint shorter than either of 

 the other two joints. The inner branches of the fourth pair 

 consist of two nearly equal joints bearing a few short setse, 

 the extremity of these branches does not reach to the end of 

 the first joint of the outer branches ; the outer branches are 

 elongate, and the second joint is shorter and the third some- 

 what longer than either of the other two. The basal joint of 

 the fifth pair forms a broad shallow lobe, bearing one siiort 

 and two long seta3, the inner one being spiniform and 

 plumose ; the secondary joint is elongate-narrow, being about 

 four times longer than broad and furnished with four unequal 

 setffi at the apex and one near the proximal end of the outer 

 margin. Caudal stylets slender and as long as the last 

 abdominal segment; each stylet bears two small setaj on the 

 inner margin, one on the outer margin, and three or four at 

 the apex. 



Hah. Vicinity of the Bass Rock. 



Remarks. Cletodes irrasa belongs to a group the distin- 

 guishing character of which is the more or less nearly obsolete 

 basal joints and the elongate and narrow secondary joints of 

 the filth pair of thoracic feet, and Cletodes Umicola, Brady, 

 may be considered the type of this group. The form of the 

 fifth pair in this group presents a marked diflference to the 

 fifth pair in those other species of the same genus that have 

 both the basal and secondary joints well developed, as, for 

 example, in Cletodes linearis, Claus. 



Thalestrisforjicidoides, sp. n. (PI. IX. figs. 4-9.) 



Length '73 millim. {.}j of an inch). Anterior antennae in 

 the female nine-jointed and provided with long slender setje ; 

 the joints gradually decrease in length from the second to the 

 fifth, while the sixth joint is one and a half times longer than 

 the fifth and equal to the combined lengths of the next two; 

 the last joint is as long as the sixth ; the proportional lengths 

 are as shown in the formula — 



