CHAP. XIV.] 



ST. HELENA. 



287 



truly aborigines, and of these all but one are found nowhere else 

 on the globe. But in addition to this large amount of specific 

 peculiarity (perhaps unequalled anywhere else in the world) the 

 beetles of this island are equally remarkable for their generic 

 isolation, and for the altogether exceptional proportion in 

 which the great divisions of the order are represented. The 

 species belong to thirty-nine genera, of which no less than 

 twenty-five are peculiar to the island ; and many of these are 

 such isolated forms that it is impossible to find their allies in 

 any particular country. Still more remarkable is the fact, that 

 more than two-thirds of the wdiole number of indigenous species 

 are Eliyncophora or weevils, wdiile more than two-fifths (fifty- 

 four species) belong to one family, the CossonidEe. Now although 

 the Rhyncophora are an immensely numerous group and always 

 form a large portion of the insect population, they nowhere 

 else approach such a proportion as this. For example, in 

 Madeira they form one-sixth of the whole of the indigenous 

 Coleoptera, in the Azores less than one-tenth, and in Britain 

 one-seventh. Even more interesting is the fact that the twenty 

 genera to which these insects belong are every one of them 

 peculiar to the island, and in many cases have no near allies 

 elsewhere, so that we cannot but look on this group of beetles 

 as forming the most characteristic portion of the ancient insect 

 fauna. Now, as the great majority of these are wood borers, 

 and all are closely attached to vegetation, and often to par- 

 ticular species of plants, we might, as Mr. Wollaston well 

 observes, deduce the former luxuriant vegetation of the island 

 from the great preponderance of this group, even had we not 

 positive evidence that it was at no distant epoch densely forest- 

 clad. We will now proceed briefly to indicate the numbers 

 and peculiarities of each of the families of beetles which enter 

 into the St. Helena fauna, taking them, not in systematic order, 

 but according to their importance in the island. 



1. Rhyncophora. — This great division includes the weevils 

 and allied groups, and, as above stated, exceeds in rmmber of 

 species all the other beetles of the island. Four families are re- 

 presented ; the Cossonidse, Avith fifteen peculiar genera comprising 

 fifty-four species, and one minute insect {Slenoscelis Jiylastoid.es) 



