WITH DESCRIPTIONS OF NEW SPECIES. 375 
in May. The species has been recorded from Scandinavia (Tragardh), 
Germany (Koch), Switzerland (Schweizer), and the North of England (Hull). 
Zercon tragardhi, sp. nov. (PI. 21. figs. 15 a, b.) 
Female. Colour pale brown. Shape broad ovate. Side margins 
strongly serrated, and the end margin is crenulate much as in Z. trigonus, Berl. 
First dorsal shield sculptured with scale-like markings, second shield with 
areolations and four crescentic pore-like markings as in Z. triangularis, Koch ; 
both shields have a double row of irregularly-shaped pits. The hair arma- 
ture is characteristic; on the side margins there are ten pairs, not including 
the frontal spines, of strongly plumose hairs (fig. 15 h). The dorsal surface 
also carries a number of spines which are less strongly plumose than those of 
the margins; short spines spring from the marginal serrations. Sternum and 
genital plate of normal shape and rather weakly chitinized. Ventro-anal 
plate large, elliptical, though somewhat flattened on the front mai-gin, with 
a few plain hairs. Legs robust and armed with plain spines, those on the 
middle segments of the first pair are somewhat stronger and are carried on 
distinct tubercles. Length 340 /t, breadth 250 fi. 
This species is allied to Z. ornatus, Berl. (3) ; the body is relatively 
narrower, and the sides less strongly rounded, the margins are more dis- 
tinctly serrated and carry fewer plumose spines. The last-mentioned 
character also separates it from Z. radiatiis, Berl. (7, p. 9), in which the 
spines are more numerous. 
Locality. Female found at roots of decaj'ed Henbane plants in August. 
Zercon peeforatulvs, Berl. 
1904. Berlese, 3, p. 260.— 1914. Berlese, 9, p. 136. 
Originally described as a variety of Z. triangularis, C L. Koch, and later 
raised to specific rank. Easily distinguished by the marking of the dorsal 
shields. In Z. triangularis these bear scale-like markings, while in the 
present species the markings are largely replaced, more especially on the 
second shield, by distinct punctures, and the hair armature also is weaker. 
Localities. Grlendalough, Co. Wicklow, found under chips of wood lying 
on the ground, April ; Knappagh Wood, Co. Mayo, in moss, August, in 
company with Z. triangularis in both localities. 
Ceratozercon bicornis {Can. et Famago). (PI. 21. fig. 16.) 
1877. Seius bicornis, Canestrini et Fanzago, 21, p. 103. — 1881. Gamasus bicornis, 
Kramer, 29, p. 14. — 1882. Lcelaps bicornis, G. et R. Canestrini, 20, p. 78. — 1885- 
Sejus bicornis, Canestrini, 18, p. 91. — 1887. Zercon bicornis, Berlese, 1, Fasc. xli. n. 8. 
—1910. Berlese, 7, p. 346. 
This species has been described and figured as having only one plumose 
spine on the two chitinous horns of the posterior margin. Instead of this, in 
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