1951] 
Christiansen — Alaskan Collembola 
139 
Variation 
The most striking variation is in the grouping and 
number of the eyes. The anterior two are often closely 
approximated or even fused, and in many cases only four 
eyes are present. The number of papillae in the P.A.O. also 
varies, from twelve to seventeen. The chaetotaxy of the 
head and abdomen varies considerably, both in number of 
setae and in the positions. The size of the setae increases 
with the size of the specimen. The number and position 
of the olfactory hairs of the fourth antennak segment vary 
somewhat (eight to ten), but only in occasional specimens. 
In a few cases the apical truncate conical area lacks a 
straight seta. The mouth parts are fairly uniform, the 
apical two teeth of third maxillary lamella may be elongate, 
and the large teeth on the mandible may be either two or 
three. 
Relationships 
This species, in the structure of the P.A.O. and in mouth- 
parts, especially in the form of the second pectinate maxil- 
lary lamella, is close to the A . granaria (Nicolet, 1847) 
group. The presence of four or five eyes removes it from 
all known species of this group. As the eyes in the new 
species are all without pigment and show other signs of 
reduction, this species may well represent a transition 
between the granaria group and those species of Anurida 
which are fully equipped with eyes and pigment. The 
present species appears to be most closely related to the 
species granaria Nicolet and pseudo granaria Stach (1949), 
but can be readily separated from both by the larger num- 
ber of olfactory hairs on the fourth antennal segment (nine 
in the present species, as compared with -six in granaria ) , 
by the long setae on the fifth and sixth abdominal seg- 
ments, and by the similar serrations on the first and third 
maxillary lamellae. 
Measurements 
Due to the great flexibility of the integument and the 
lack of clearly marked imbricate or setaceous areas, at- 
tempts to derive satisfactory ratios were fruitless. Thus 
