WITH DESCRIPTIONS OF NEW SPECIES 23 



bb. Size smaller ( 1 '5 mm.). Cerci with fewer and 

 longer setae and without the long outstanding 

 setae on either the upper or lower margin. 

 Setae on scuta well-developed ; second scutum 

 with three long and two short intermediate setae 

 between those above-named (act). Three setae 

 on tarsus of hind leg. Very slender. 



minutissima, Bagnall. 



Genus SCUTIGERELLA Ryder 



Group I. — Posterior margin of the last dorsal scutum with 

 a deep anteriorly-overlapped median cavity. 



A. — Thirteenth scutum normal; surface of all the scuta 

 rather closely and minutely setose ; cerci longer and narrower, 

 generally closely and minutely setose ; tactile hairs on the last 

 segment short and very fine. 



AA. — Size larger, seicc on cercus more minute (about one-fifth tke depth 

 of cercus) and more numerous. Seta on legs shorter, less con- 

 spicuous, and more numerous. 



Scutigerella immaculata Newp. (PI. I., figs. 1-2.) 



As it is probable that several of the British records of this 

 species refer partly or wholly to other forms, the following are 

 the data of several specimens I have myself examined. 



Professor Hansen has recorded British examples submitted 

 by Mr. Pocock, from Devonshire. 



Fig. 1. Scutigerella immaculata. 



A. Metatarsus and tarsus of last left leg X 60. 



B. Tarsus of left front leg X 60. 



