A. D. MICHAEL ON A SPECIES OF GAMASUS. 263 



the most marked and obvious manner. I found it in the moles' 

 nests, and brought home and preserved nests and all in their 

 natural condition. I had plenty of specimens of the Gamasids, 

 and they were amply supplied with the vegetable material in 

 which they lived, but I did not ever find them feeding upon 

 any vegetable matter; whereas, both when I first obtained 

 them, and afterwards during the time I kept them, I was con- 

 tinually finding the Gamasids with small wire-worms and other 

 larvae of beetles, &c, and small worms, and even mole-fleas 

 in their mandibles. The larvae were often so large that they 

 dragged the Gamasus about while he was devouring them ; but 

 the Gamasus always held on, and sucked his victim quite dry. 

 Sometimes he would kill it by darting his lance-like mandibles 

 through and through it. All these processes were easily watched 

 under the microscope, and when I wanted to keep a Gamasus 

 alive in a separate cell for observation I fed it on soft-bodied 

 larvae, which answered admirably. For its size, this Gamasus is 

 one of the most ferocious creatures I ever had to deal with. 



The above-named use is not the only mode in which the 

 mandibles are employed. I was quite unprepared for another 

 purpose to which I found that they were applied. The great 

 difference between the mandibles in the two sexes, and 

 their singular development in the male, naturally lead the 

 observer to suspect that in this sex they might subserve some 

 sexual purpose ; but on reflection it seemed, perhaps, more 

 probable that they were merely correlated. I observed in the 

 specimens that I had killed for preparations that the two 

 mandibles were always extruded to the same extent ; now, the 

 ordinary, strongly-chelate mandibles of Gamasids are more 

 usually extruded alternately, and then specimens which have 

 been killed are found with the two mandibles unequally 

 advanced. I, therefore, suspected that in this species the 

 mandibles might be protruded at the same instant. I carefully 

 observed the living creature, and found that this was always 

 so. It, however, had not any particular significance for me 

 until after I had made other observations. It so happened 

 that I found a considerable number of males and females in 

 coitu. I noticed that the mandibles of the male were bent 

 downward toward the female in a manner which seemed to 

 me singular. On separating one of the males from its com- 



