1867.] MR. G. R. CROTCH ON AZOREAN COLEOPTERA. 3G5 



unchanged; the Homalium and Phlceophagus are the only two 

 "autochthones." 



Their connexion with the Canaries is very slight and little marked, 

 114 species only being common to the two groups. Of these — 



(1) Ninety-seven are, as before, universal. 



(2) Seven are common also to Europe ; and four of them, at 

 least, are introduced. 



Hydroporus planus. Anthicus humilis. 



Gyrinus dejeani. Ocypus olens. 



Dermestes frischii. liomalota nigra. 

 Trachyscelis aphodioides. 



(3) Eight are, as before, common to Madeira. 



(4) Two only remain as peculiar to the Canaries and Azores ; 

 and of these one (^Anobium villosuin) is a mere introduction ; but 

 the other {Calosoma azoricum) is a very singular insect, representing 

 the C. inaderiB of Madeira, and extending even to the Cape de Verde 

 Islands. The Canaries are remarkable for possessing both forms, 

 though in separate islands. 



With the little uninhabited rocks called the Salvages, the Azores 

 have two species in common {Harjmlus rotundicoUis and Phaleria 

 himacidata), both occurring in some abundance. 



But the most remarkable portion of the Azorean fauna remains 

 yet to be noticed, viz. those species which it has in common with 

 America. These are — 



j^olus melliculus. Tceniofes scalaris, 



Monocrepidius posticus. 



The Heteroderes azorleiis also is probably a mere modification of 

 an American species, which has succeeded in establishing itself here. 

 The Tceniotes also appears thoroughly naturalized. Whether these 

 species owe their introduction to colonization and human intercourse 

 or to natural means must remain an open question. For the former 

 much is to be said. An open and continual communication exists 

 between S. ISIiguel and Bahia ; and Mr. Godman informs me that 

 very large quantities of plants and trees are imported to form gar- 

 dens. This latter fact may account for the numerous European 

 species also. On the other hand, the occurrence of Chjtus erythro- 

 cephalus on the desolate rocks of the Salvages, where it could not 

 have been introduced, suggests that, after all, the Gulf Stream may 

 have been the origin of tbesc peculiar species. This is borne out by 

 the fact that they are all wood-feeding species, so that they would 

 readily come in logs in the pupa state without injury ; and by the 

 fact that the Ilet. azoricus must have been introduced at a period 

 previous to the Portuguese colonization to account for its abundance 

 in several islands and its modified characters. Some light may be 

 thrown on this also by the occurrence of Ci/7if/iia huntera in the 

 Canaries. 



Further, an African connexion is suggested by the Staphylimts 

 hesperus (a close ally of a Cape species), and by the very remarkable 



