GAMASWS. 



159 



CASE from the stone under which they have taken refuge, unless they 

 are kept moist. The insects on which they live are chiefly sub- 

 terranean, making burrows in damp soil, or under cow dung, &c. 



Nos. Gamasus marginatus (Z>z/^.).— 3. Enlarged figure of ditto ; 4. Specimens. 



3.4- 



Gamasus marg-inatus. 

 About J line in length. 



Gamasus (Laelaps) hilaris. Copied from Koch's figure. 

 About the size of a pin's head. 



Broader, rounder, and darker in colour than the last, and with- 

 out the transverse soft white space across the back, but with the 

 marginal space wider, especially behind. This species is also 

 found on beetles more frequently even than the last, and some- 

 times along with them ; but, generally speaking, more than one 

 species of mite is not found on the same beetle. Hermann, in 

 his Memoire Apterologique, reports that this species lives on dead 

 bodies, and cites the curious fact that one was observed by his 

 artist running on the corpus callosum of the brain of a soldier 

 who died in the miHtary hospital at Strasburg, which had been 

 opened but a minute before, and the two hemispheres and the pia 

 mater just separated. Hermann thought not, but we have no 

 doubt that it was merely a case of first come, first served. 

 Prompt as the doctors had been with their examination, the mite 

 had been prompter. 



Koch has established a genus which he has named Laelaps, 

 and the only character wherein it differs from Gamasus is in not 



