336 



ISLAND LIFE. 



[part II, 



numbers are, generally speaking, proportionate to the richness of 

 the district and the amount of work bestowed upon it ; Scotland, 

 however, giving more than its due proportion in this respect, 

 which must be imputed to its really possessing a greater amount 

 of speciality. The single peculiar Irish species stands as a monu- 

 ment of our comparative ignorance of the entomology of the 

 sister isle. The peculiar species of Apion in the Shetland 

 Islands is interesting, and may be connected with the very 

 peculiar climatal conditions there prevailing, which have led in 

 some cases to a change of habits, so that a species of weevil 

 {Otiorhynchus maurus) always found on mountain sides in Scotland 

 here occurs on the sea-shore. Still more curious is the occur- 

 rence of two distinct forms (a species and a well-marked variety) 

 on the small granitic Lundy Island in the Bristol Channel. 

 This island is about three miles long and twelve from the coast 

 of Devonshire, consisting mainly of granite with a little of the 

 Devonian formation, and the presence here of pecaliar insects 

 can only be due to isolation with special conditions, and im- 

 munity from enemies or competing forms. When we consider 

 the similar islands off the coasts of Scotland and Ireland, with 

 the Isle of Man and the Scilly Islands, none of which have 

 been yet thoroughly explored for beetles, it is probable that 

 many similar examples of peculiar isolated forms remain to be 

 discovered. 



Mr. Rye hardly thinks it possible that the Dromius vedensis 

 can really be peculiar to the Isle of Wight, although it is abun- 

 dant there, and has never been found elsewhere ; but the case 

 of Lundy Island renders it less improbable ; and when we con- 

 sider that the Arum italimm, Calamintha sylvatica, and perhaps 

 one or two other plants are found nowhere else in the British Isles, 

 we must admit that the same causes which have acted to restrict 

 the range of a plant may have had a similar effect with a beetle. 



I must also notice the Cathormiocerus maritimus, because 

 its only near ally inhabits the coasts of the Mediterranean ; and 

 it thus offers an analogous case to the small moth, Machista 

 ru/ocinerea, which is found only in Britain and the extreme 

 South of Europe. Looking, then, at what seem to me the proba- 

 bilities of the case from the standpoint of evolution and natural 



