512 Mr. E. I, Pocock on the MoriJiology 



A. Plagiostethi ( = ralpatores). 



a. Apagostemi. 



b. Eupagosterui. 



B. Mecostetht. 



a. Insidiatores. 

 h. Laniatores. 



C. Cyphophthalmi (= Anepiguatlii *). 



Tlie cliaracters separating the Apagosterni and Eiipago- 

 sferni, however, are of nmch higher value, in my opinion, 

 than those separating the Insidiatores and Laniatores. The 

 sternal plate of the prosoma in the Laniatores sliows great 

 constancy in shape as compared with that of the Insidiatores. 

 Tiie Laniatores are divided into several families, in all of 

 which the sternum exhibits but little variation from the 

 normal characteristic of the Mecostethi. It seems logical, 

 therefore, to conclude that when striking variations from this 

 type are met with in the Insidiatores, such variations, if 

 constant, should form the basis for the establishment of 

 groups of " family " rank. I propose consequently to divide 

 the Insidiatores, which by Sorensen and Loman are considered 

 to be represented by the single family Trifenonychidpe, into 

 the following groups of this rank, postulating that the struc- 

 tural features on which they rest have at least the same value 

 as those used for the same purpose in the Laniatores : — 



a. Sternum very narrow and compressed be- 

 tween the coxae of the appendages of 

 the hfth pair, abruptly expanding be- 

 tween those of the sixth, and showing 

 a lanceolate or narrowly cordate expan- 

 sion opposite the line of junction of the 

 coxae of the fourth and fifth pairs of 

 appendages. 

 «\ I'osterior expansion of sternum nar- 

 row, subpentagonal, not wider than 

 long, much nan-ower than the length 

 of the area between the fifth ap- 

 pendages ; stigmata exposed Fam. Tbi;enonychid^. 



6\ I'osterior expansion of sternum trans- 

 versely arcuate, laterally pointed, 

 much wider than long, much wider 

 than the length of the narrow area 

 lying between the coxae of the fifth 

 appendages ; stigmata concealed .... Fam. Tri^nobunid^, nov. 



* This name is of later date than Cyphophthalmi, and was based 

 upon a misconception. 



