Review of the Genus Hrebia, 223 
described as if it were a member of the glacialis group ; 
it has a rather broad body, without styles. The lobe is 
prominent, triangular, and ends in one very large style. 
The neck and head are about one-fourth of the clasp in 
length ; in the curve from the lobe to the head are from 
two to four very large styles, and the head terminates in a 
bundle of moderate-sized styles. 
2. E. tyndarus (Fig. 24). This, in its best- 
developed form, and the one that approaches nearest to: 
ottomana, has only three large styles, of which the first 
probably represents the lobe and is sometimes on ea slight 
eminence, but often so slight that the three styles appear 
to be seated on a uniform sweep or curve reaching from 
the base to the head. The head has no styles, but has a 
rounded termination, carrying a fascicle of strong hairs. 
Sometimes the first two styles are conjoined. In var. 
sibirica there are only two followed by some very fine 
teeth. In var. callias, the spine representing the lobe is 
usually recognisable but is close down to the head, which 
has at its upper margin a number of styles, and below has 
the same rounded end as in typical tyndarus. The 
amount of variation in both Kuropean and American 
tyndarus is so great, and so mtch bridges over the differ- 
ences, that I do not think ca/lias can be recognised as 
distinct, but it is certainly very nearly so. Ottomana is 
in a different position, as, besides the pronounced pro- 
jection of the lobe and the great number of large styles, 
there is a real structural difference in the presence of the 
styles at the extremity of the head. It has also not only 
a much larger, but a proportionally longer central process 
to the sickle. It is also much larger. The Spanish 
forms, hispana and pyrenaica, do not differ from the Central- 
European forms. 
The dimensions and proportions, as given in the last 
group, are in millimetres as follows : 
Length Length of 
of Head and Proportion. 
Clasp. Neck. 
Tyndarus, Carinthia . 1°44 “40 ‘28 
e Switzerland. 1:44 *20 "14 
a var, stbirica. 1:45 "30 “21 
2 var. callias , 1°40 ‘10 ‘OT 
Oitoman@ ... 5 2 2°00 *48 "24 
Fipistygné . . 5 « ss 2°00 40 20 
