608 IVAR TRAGARDH 
There is, in my opinion, only one way in which to account for this highly 
aberrant number of hairs in Seus viz. to assume, that in this genus the epi- 
gynial shield is not homologuous to the epigynial shield of other Mesostigmata 
but consists of this shield fused with elements of a ventral shield which has 
the supernumerary hairs. There is, however, a serious obstacle to this theory, 
viz. that the lateral sides of the epigynial shield project as free blades and 
cover the base of coxz III and IV. 
Of the sternal hairs one pair is inserted in front of the middle of coxe 
II and as far from the anterior as from the lateral side, one pair is inserted 
on a pair of small, rounded, faintly discernible shields near the median line and 
in front of a faint semicircular suture, 
which is the anterior border of a 
transversal shield which forms the 
anterior lip of the genital aperture 
and which bears two pairs of hairs. 
The genital aperture is situated 
far forwards, in front of the posterior 
margin of cox II and is shaped as 
a narrow fissure, curved in an even 
curve backwards. The genital shield 
is much longer than in S. sogatus, 
with convex sides and truncated at 
the posterior end on a level with the 
hind margin of coxe 1V. Of the 3 
pairs of hairs? one is inserted on a 
level with the middle of coxe III, 
one in the angle between coxz III 
and IV and the last pair near the 
anterior margin of coxa IV. | 
The peritrematic and parapodial 
shields are fused, but the metapodial 

119 118 
Figs, 118—120. Sejus znsulanus n. sp. shields are free and triangular, with 
118. Left half of ventral side. 119. Sternal and 
genital shields. 120. Mandible. rounded sides and angles except the 
anterior one which is sharp (fig. 118). 
Ventri-anal shield large, with well rounded posterior margin and almost 
straight anterior margin, and granulated surface. Between the shields there 
are projections of the same shape as the marginal ones, carrying curved hairs. 
The legs are short and stout, richely provided with projections bearing 
hairs, similar to the marginal ones. 
Mouthparts (fig. 120); of these I have only been able to examine the 
mandibles. The lower jaw is slender, only slightly curved, with short terminal 
tooth and further backwards a small tooth. The upper jaw is more than twice 
as big as the lower one, with sharp terminal tooth, the cutting edge with two 
small teeth and further backwards a dense row of very small teeth. 

‘ Owing to the bad state of preservation of the single specimen I have not been able to 
ascertain the presence of the 4th pair of hairs present in S. fogatus (comp. TRAGARDH 1912, 
Mg. 29). 
