1951] 
Christiansen — Alaskan Collembola 
25 
with mucro, dens, and manubrium all distinct. Manubrium 
ventrally with a few large setae, dorsally with many short 
setae; dens dorsally with a few broad humps, and a few 
scattered setae ; mucro with several teeth. Dens about twice 
as long as mucro. Rami of tenaculum quadridentate, corpus 
with a single stout seta. Legs stout; tibiotarsus possessing 
minute distal subsegment; claw simple, all feet with well- 
developed empodial appendage. Externally at the base of 
each leg a single large, straight seta ; on legs two and three 
there are in addition two slightly smaller curved setae. 
Integument finely reticulate, that is, possessing a net- 
work of thin, flat ridges, with the intervening areas slightly 
depressed. Head, antennae, and imbricate areas of the ab- 
domen and thorax well pigmented, with scattered pale spots. 
Intersegmental membranes, legs, and furcula unpigmented. 
Clothing of smooth, short, slightly curved and appressed 
setae ; a few longer, upright setae on the sides and posterior 
regions of the body. Bothriotrichia absent. 
Weberacantha octa, n. sp. 
Holotype. Pigment blue with scattered white spots^ 
larger and more numerous on the head and anterior borders 
of segments than elsewhere. Intersegmental membranes, 
legs, and dentes white. First thoracic segment white, with 
Text-figure 1: Weberacantha octa, habitus, holotype (setae omitted)'. 
scattered pigmented areas. Antennae slightly paler than 
body; anal spines and mucro yellow. Reticulations on the 
imbricate areas of the thorax and abdomen more or less uni- 
form, those on the head region being slightly larger and 
more irregular in shape; reticulations of intersegmental 
