180 

 Gen. 40. Stenhelia, Boeck, 1864 (not Brady). 



Syn : Delavalia, Brady. 

 Beatricella, Scott. 



Generic Characters. Body more or less pyriform in shape, with the ce- 

 phalic segment very large and tumid. Rostrum quite immobile, though distinctly 

 defined at the base, forming a broad triangular plate slightly indented on each 

 side of the tip, and provided ventrally with a projecting carina. Epimeral plates 

 of the 3 succeeding segments small, rounded. Urosome comparatively short and 

 gradually tapered behind. Caudal rami more or less produced, with the normal 

 number of setae. Eye well developed. Anterior antennae comparatively short and 

 densely setiferous, 8-articulate, with the joints of the proximal part very sharply 

 defined and gradually diminishing in size; those of male transformed in the usual 

 manner. Posterior antennae with the terminal joint rather large, apical spines 

 scarcely geniculated, outer ramus well developed, triarticulate. Mandibles very 

 strong, palp large, with the basal part much produced, inner ramus bent abruptly 

 backwards, and carrying on the tip a very strong, elongated falciform seta, 

 accompanied by one or two smaller ones, outer ramus very delicate, forming a 

 thin setiferous lamella. Maxillae and anterior maxillipeds of normal structure. 

 Posterior maxillipeds very small, in some cases not prehensile. 1st pair of legs 

 of exactly the same structure in the two sexes, outer ramus triarticulate, inner in 

 some cases distinctly 3-articulate and prehensile, in other cases composed of only 

 2 joints. Natatory legs strongly built, with both rami triarticulate and nearly 

 equal in size, except in the 4th pair; inner ramus of 2nd pair in male transformed. 

 Last pair of legs with the distal joint very mobile, forming a more or less broad 

 lamella generally extended laterally; inner expansion of proximal joint short and 

 broad; those in male much smaller than in female, in some cases quite rudimen- 

 tary. Ovisacs more or less divergent, sub-lateral. 



Remarks. This genus was established in the year 1864 by Boeck, to 

 comprise 2 Norwegian species, viz., 8. gibba and S. longicaudata. Brady wrongly 

 referred to this genus 2 species belonging to the genus Amphiascus, as here de- 

 fined, whereas 3 other species, which undoubtedly belong to Boeck's genus, wero 

 referred by him to the new genus Delavalia, and all subsequent British authors havo 

 followed Brady in this respect. Dr. Giesbrecht also described a species of Am- 

 phiascus as a Stenhelia, though he seems to have been aware of the disagreement 

 of Boeck's definition of the genus with that given by Brady. The genus Beatri- 

 cella recently established by Th. Scott is also unquestionably identical with Boeck's 

 genus, being indeed founded upon the type of the latter genus. The most pro- 



