1888.] 123 



all others by the peculiar construction of the antennae, that it is one 

 of those species that can be most easily recognised. Thus, improbable 

 as it may seem, it is undoubted that the specimens inhabiting the 

 snow-fields of the Sierra Nevada, and a sandy spot on the shores 

 of the Isle of Wight, are one and the same species. 



The series obtained from these two localities we have also com- 

 pared with specimens of G. maritimus, Rye, found at Portsea, by 

 Moncreaff, and find them quite certainly a distinct species. 



It will be seen, therefore, that the views of Eye were quite cor- 

 rect, and it is owing only to their having been neglected by subsequent 

 writers that confusion again prevails. 



W e have not seen any examples of G. socius or G maritimus from 

 other sources than those we have just mentioned, and we are not, 

 therefore, in a position to say whether the French examples pertain 

 to G. socius or to G. maritimus, or to both, or to neither. In order, how- 

 ever, that this may be decided, we give the following remarks on the 

 scape of the antennae in the two species. 



In G. socius the scape of the antennae is abruptly incrassate 

 immediately it leaves the scrobe, and in addition to this, the scape 

 possesses a rather large supernumerary incrassation on its posterior- 

 inferior face, this incrassation being quite close to the scrobe. In G. 

 maritimus the dilatation of the scape does not commence at the base, 

 but a well-marked more slender portion intervenes. If the antennae 

 of the two species be dis-articulated, it will be found that the basal 

 portion is very differently constructed in the two, but as our object is 

 merely to point out a single character by which the two can be readily 

 distinguished, we need not refer to this and other distinctions in 

 detail. 



"We may add that there is no sexual difference in the form of the 

 scape, nor have we detected any variation therein ; the examples of G. 

 socius from the Sierra Nevada being quite similar to those from the 

 Isle of Wight. 



When we know more of the distribution of these two species, we 

 may, perhaps, be in a position to make some guesses connected there- 

 with. It certainly is a most extraordinary fact that a very rare and 

 very distinct species should be found on the snow-fields of the Sierra 

 Nevada, and in an arid spot in the Isle of Wight ; and if it should 

 prove to be absent from intervening localities, the species will be a 

 greater puzzle biologically than it has proved at present to be nomen- 

 clatorically. 



September 15th, 1888. 



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