Entomological Society. 4625 



the rocks," being peculiarly unfavorable to the preservation of insect 

 life : this is a reasonable solution, but how shall we account for the 

 absence of Cerambycidae from this island of woods ? and how shall 

 we account for the great scarcity of all flower-loving Coleoptera, ex- 

 cept on the supposition that their office of pollen-bearers is performed 

 by the hosts of Hymenoptera and Diptera. Mr. Wollaston's remarks 

 on the effects of isolation on species are worthy of deep study and 

 attention ; they will be found appended to the descriptions of Scarites 

 abbreviatus, Calathus complanatus, Harpalus vividus, and the Ptini : 

 after alluding to the two sections of the latter, the author proceeds to 

 say that " the representatives of both are subject to very great variation 

 in size and colour, and, since even the sexes themselves often display 

 considerable incongruity, inter se, it is not surprising that the bounda- 

 ries between some of the species which are nearly allied should be 

 difficult to trace out. Such being the fact, it is impossible to overrate 

 the importance of studying them in situ, so as to be enabled not only 

 to connect the numerous aberrations, but even at times, perhaps, in a 

 certain measure, to account for them ; since it is by this process of 

 inquiry that we are more likely to arrive at truth, than by the collation 

 of treble the amount of individuals, at a distance, when anything like 

 local phenomena in connexion with them must be entirely overlooked. 

 So completely, indeed, are some of the Madeiran Ptini affected by 

 isolation, and by an exposure to a perpetually stormy atmosphere, that 

 they do not attain half the bulk on many of the adjacent rocks that 

 they do in the more sheltered districts of the central mass ; and so 

 marvellously is this verified in a particular instance, that I have but 

 little doubt that five or six species, so called, might have been re- 

 corded, had only a few stray specimens been brought home for identi- 

 fication, without any regard having been paid to the respective 

 circumstances under which they were found. Judging from many 

 hundred examples which I have submitted to a close comparison, the 

 most constant of their characteristics would appear to be outline and 

 sculpture, whilst size and colour are apparently the least to be de- 

 pended on, and hence trifling differences may be often of specific 

 indication in the former case, where in the latter much larger ones are 

 worthless." Again, the observations on Tarphius, one of the Colydi- 

 idae, a family of Necrophaga, are replete with interest : prior to the 

 publication of Mr. Wollaston's work a single species was known, and 

 this of the greatest rarity ; it was taken in Sicily by the late lamented 

 Coleopterist Mr. Melly. Mr. Wollaston has added no less than fifteen 

 Madeiran species, all of which appear to be abundantly distinct. " Of 



