568 IVAR TRAGARDH 
ventral edge of the cusp projects so far that the oval opening is turned straight 
upwards. The inner, funnelshaped portion has concentrical ridges and is bent 
forwards. Pseudostigmatic organ with thin peduncle, almost twice as long 
as the head, and curved in the proximal part in an even curve outwards and 
forwards, the distal part being bent slightly forwards and then outwards like 
an S. The head is almost four times as long as it is wide; its surface has 
small rough points, arranged in longitudinal rows. 
Hysterosoma (fig. 22) covered by an oval shield a little pointed an- 
teriorly and a little more obtuse posteriorly. The shield is very slightly arched 

Figs. 20—21. Plateremeus vestitus n. sp. 
20. Dorsal view. 21. Ventral view. 
with very little pronounced longitudinal ridge. Its texture is beautifully reti- 
culated through shallow, circular or oval depressions; along the margin there 
is a narrow strip where the cuticle seems to be thinner and has no sculpture, 
but the more chitinized margin has the same reticulation. There are only three 
pairs of minute hairs at the posterior end. On the shield there are 6 pairs 
of marrow pores, shaped like slits; they are through a fine, more or less 
central canal connected with the subcuticular tissue (fig. 26). Very possibly 
through them some fluid is secreted which makes the nymphal skins adhere 
to the shield. 
The shield is covered by one larval and 3 nymphal skins. The skins 
are very thin and fragile and have an irregular, netlike texture, without any of 
the radiating striz so conspicuous in (Veolzodes. The centre of the larval shield 
