Seychelles and Rauijoon. 7 



Types. — A first set of the material, incliuliiig the types of 

 the new genus and of all new species, will be placed in the 

 British j\liiseiim ; a second set will be retained in the Cam- 

 bridge University Museum. 



SaciUM, Leconte. 

 (PI. T. tigs. 1-9.) 

 Sacium, Leconte, Proc. Ac. Philad. vi. 1852, p. 142. 



The material includes four species from the Seyclielles, all 

 quite distinct from each other and from anything in Matthevvs's 

 culiection ; neither do the descriptions of the few species 

 which I have not seen correspond at all with any of the 

 ►St-ychelJes forms. Reitter (1908) has described five species 

 from East Africa ; but after careful study of his descriptions 

 1 conclude that none of my species is identical with any of 

 his. 



Structural Characters. — In examining the Seychelles 

 collection I have noticed certain structural differences between 

 the species, of a kind which does not seem to have been 

 hitherto employed. Thus, among these four species there are 

 two distinct types of p^'ostemum : (i.) of appreciable lengtU 

 in front of the coxoe and furnished with an elevated median 

 keel (fig. 6) ; (ii.) exceedingly short in front of the coxa? and 

 with no keel (tig. 3) ; turtlier details are given in the 

 specific descriptions. Matthews (Mon. p. 41) writes " pro- 

 sterno parvo, inter coxas elevato . . .," but makes no state- 

 ment as to specific ditferences in its form. 



Another category of characters is exhibited by the mouth~ 

 parts. A balsam-preparation was made in order to fix with 

 certainty the generic position of each species. These prepara- 

 tions exhibit slight differences in the form and relative pro- 

 portions of such parts as the mentum and joints of the palpi, 

 differences which are briefly mentioned in each description 

 (c/. figs. 2, 5, 8, 9). 



Ciiaracters such as these are not necessary for separating 

 the Seychelles species, which are amply distinct in other 

 ways. But they are indicated in ca.se they should prove 

 usefid in further studies of this large genus of nunute 

 creatures. 



1. Sacium picauUiamnn, sp. n. 

 (PI. I. figs. 1-6.} 



Oblongo-ovale, supra nitidissimum, fere glabrura ; piceo-uigrnra, 

 thoracis margiue anteriore testaceo, elytris maculis 4 (in utroque 



