522 Mr. A. R. Wallace's Catalogue 



which so nearly resemble each other that it seems 

 impossible to separate them, but close examination 

 reveals minute but important differential characters 

 which seem quite constant. Such are Macronota carbo- 

 nari ci and M. egregia, var. nigra ; Scldzorliina Whitei and 

 S. houruensis ; Lomaptera arouensis, L. cerar)iensis , and 

 L. cambodiensis ; Lomaptera pygidialis and L. batclviana, 

 and some others. Such cases force us to the conclusion 

 that structural and superficial characters are about on 

 a par as regards introducing any certainty into the 

 definition of a species, and that a decided difi'erence of 

 colour and marking is often a better character than a 

 slight modification of the form or sculpture of some 

 important organ. Both are sometimes very constant, 

 both are at times liable to much variation, and it is 

 a matter of judgment and opinion how far we are to be 

 guided by either in any particu.lar case. 



It will be as well, to avoid misapprehension, to say 

 a few words about the localities given for the various 

 species. All the specimens noted as from my collection 

 were either obtained directly by myself in the localities 

 named, or through collectors whom I knew well. All 

 these localities therefore may be relied upon as perfectly 

 authentic. The specimens collected by Mr. Lamb, and 

 noted as from " Penang-,'' were most of them collected, 

 not in the island, but in the main land of the Malay 

 Peninsula opposite, termed the "Province of Wellesley." 

 " Penang" may therefore be held to signify merely a parti- 

 cular sub-district of the Malay Peninsula. The collections 

 presented to the British Museum by Mr. Bowring com- 

 prise several thousand specimens labelled " Java." 

 These were not collected by Mr. Bowring himself, but 

 formed part of an extensive collection purchased by him, 

 and said to have been collected in " Java and the adja- 

 cent islands," — but chiefly in Java. It is to be remem- 

 bered also, that for the last hundred years, collections 

 have arrived in Euro])e from Java, which did not neces- 

 sarily consist only of Javanese insects,- — sometimes, on 

 the contrary, they have been entirely formed in other 

 islands. It follows that my own collections and those of 

 Dr. Horsfield are the only perfectly authentic materials 

 for the Entomology of Java, although I fully believe 

 that by far the larger part of the species imputed to that 

 island do really inhabit it, since it is unusually rich in 

 every department of Zoology. The specimens from the 



