^5 



Heinanl (1894. 48. p. 411) bul the latter in a very imperfect manner. The last 

 publication on this theme is that of StschelkanovtzefV (1903. 67. p. 320) of Chelifer 

 cimicoides F. Because none of these authors have observed the fundamental dif- 

 ferences between the difTerent forms or made any comparison between them, I 

 prefer to compare their studies with mine in each single case. My researches 

 respecting this theme do not go very deep, as I had not material sufficiently well 

 preserved for investigating the minute structures of the labium and sucking organ; 

 my object is only to give a description of the modifications in the main genera, as 

 far as the outer structure is concerned, and where it is possible a comparison 

 between them. 



I. Chthonius C. K. (PI. I, figs. 1 e-g, fig. 2 a). 



The labrum is as usual placed between the maxillae and dorsally in the 

 middle coalesced with their inner margin. Its front part is a free slightly pointed 

 projection, which is situated on a lower level than the rest and mounted with 

 clear prominences, similar to hairs (PI. I, figs. 1 e-f). The labrum merges behind 

 into a rounded, posteriorly more narrow projection, as long as the labrum proper 

 (fig. 1 e, p). The skin of the labrum is between the maxillae granular and besides 

 in the middle transversely striated. The hindmost projection seems at least in 

 Chth. Rayi L. K. to be a simple plate without granulations. A well developed 

 labium as well as a complicated sucking organ is observed, the structure of which 

 1 do not treat on here. 



The maxillae of Chth. terribilis n. sp. is as seen from the upper side, laterally 

 prolonged backwards with the hinder margin curled over upwards (fig. 1 e). They 

 slope moderately laterally and posteriorly, and become narrower between the 

 trochanter and the anterior portion of the labrum, but especially in front of the 

 trochanter (PI. 1, fig. 1 e). The thus established manducatory part is moderately 

 pointed and has the outer margin just behind the tip curled over upwards and 

 jjrovided with two hairs (PI. 1, fig. 1 f). Near to the base of the terminal or man- 

 ducatory part a membranous clear plate is situated, which is directed forwards 

 and upwards, enlarged distally and mounted with marginal teeth anteriorly; this 

 l)late may properly be named lamina maxillaris superior (fig. 1 f. Is). Along the inner 

 margin of the manducatory part an other membranaceous plate is situated, which 

 is pointed and on a level with the maxilla ; this plate is consequently designated 

 lamina maxillaris inferior (PI. 1, fig. f, /;"). These two laminae as well as the man- 

 ducatory portion, have in Ch. Rayi L. K. another shape; the lamina superior is 

 pointed, and so is the slightly developed lamina inferior (cf. PI. I, fig. 2 a, Is-li). 

 The maxilla itself is in this species everywhere mounted with plate-shaped granules 

 or more correctly divided into a mosaic of square plates. The maxillae of Ch. 

 terribilis n. sp. are, when observed from below, seen to be somewhat longer than 

 broad and has the manducatory part ]jlaced on a higher level than the posterior 



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