Natural-History Collectors. 



6169 



are on this account both most interesting groups. In ornithology the 

 same phenomena are offered very conspicuously in the TrochiUdae and 

 Rhamphastidae. It appears clear to me the inference, on this account, 

 that such groups are of recent date, geologically speaking, and are 

 most characteristic of the present epoch of the earth's surface. At 

 Ega the most conspicuous species of Erotylus is E. incomparabilis 

 Perty ? accompanying which are four or five others. At Caigara, 

 twenty miles above Ega, this species exists as a marked variety ; at 

 Tabatinga its place is occupied by a distinct, but similar, form; and 

 at St. Paulo I found it, as well as all its companion species, represented 

 by a set of quite different species. In this group, as well as in all 

 similar groups, the species should be studied with close reference to 

 the localities in which they are found. Hence we see how excellent 

 is the system adopted by the British Museum, which tickets every in- 

 dividual specimen (at least in the Lepidoptera) and comprises 

 specimens of each species from different points of its area of distri- 

 bution. 



In concluding these rambling notes, I must not forget to record 

 also, in illustration of the position, the locality of St. Paulo occupies 

 in the geographical distribution of Amazonian insects ; that many 

 common species found generally from Para upwards, also occur there. 

 Some, such as Papilio Sesostris, Epicalia Numilius, Acontius, and 

 many others do not vary in the least, whilst those which have become 

 very much altered from Para to Ega, are become still further altered 

 from Ega to St. Paulo : this is particularly the case with Mechanitis 

 Lycidice, and I think others of the same genus. I think a great 

 number of species will be found affected in a similar manner ; they 

 can be best studied at the British Museum, where the specimens 

 from the different localities are doubtless to be seen together, as also 

 others from New Granada and the slopes of the Andes. 



On the whole, I brought rather more than 5000 specimens of 

 insects from St. Paulo ; amongst which there were 686 species new to 

 me of all orders ; 79 being new species of Diurnal Lepidoptera. 



Henry Walter Bates. 



XVI. 



