i6o ARACHNOIDEA, 



CASE having the anterior legs slenderer and longer than the rest; in 

 other respects it corresponds with the section containing Gamasus 

 marginatus ; but the elongation of the anterior legs does not seem 

 a generic character, but rather one of degree; indeed. Koch's 

 own figure of Laelaps hilaris, of which we give a copy, does not 

 bear out his own diagnosis, the anterior legs in it being both 

 longer and slenderer than the other legs. We have, therefore, not 

 adopted the genus Laelaps. 



Gamasus hilaris (Laelaps hilaris, Koch, Ubers., p. 88, t. x., f. 48). 



Koch says that this species and three others belonging to the 

 same genus Laelaps are parasitic on mice, although he never 

 found any on the house mouse. He regards them as specially 

 assigned to mice, and only to be found upon them. This figure,, 

 however, looks so like other Gamasi which are found wandering 

 at times, that it may be well to wait for confirmation of Koch's 

 assumption before definitely adopting it. 



There are several species formed upon the same plan as these, 

 which are difficult to distinguish from each other. Koch describes 

 about a score. One is the G. testudinarius of Hermann. We 

 possess another of comparatively large size and very pubescent, 

 with a fringe of long hairs on each side, especially in front. It 

 was taken from the under side of the neck of Phanseus lancifer, 

 a large South American dung beetle. The portion disclosing 

 the soft skin is in it larger than usual. Duges mentions a 

 very large species which he, too, found on a Brazilian Copris 

 (C. mimas), and which, from its size, he called Gamasus gigas. 

 He says it was as large as our common Ixodes. If he means 

 the male Ixodes, it may be the species of which we have been 

 speaking, which then would sufficiently correspond with his 

 description. If a replete female Ixodes, then it must be some- 

 thing different. We have several other species taken from 

 beetles from different countries differing but slightly in size, but 

 probably distinct. 



