186 THE ZOOLOGIST. 



On the 17th March, 1859, Bates returned to Para, "a wreck 

 of his former self." No constitution could withstand the con- 

 tinued strain of climate, poor living, frequently actual hunger 

 and exposure which he so long endured ; and it is evident that 

 nothing but physical prostration brought about his long deferred 

 return to England, which he reached in a condition which rendered 

 him more or less an invalid for the rest of his days. 



During the eleven years that he passed in South America, 

 several articles from his pen appeared in ' The Zoologist.' The 

 first of these, on the habits of the Douroucouli Monkey, dated 

 Para, Oct. 7th, 1851, was published in ■ The Zoologist ' for 1852 

 (p. 3324), and was succeeded shortly afterwards by a most inte- 

 resting article entitled " Some Account of the Country of the 

 Kiver Solimoens or Upper Amazons " (torn. cit. pp. 3590—3599). 

 This was followed at intervals by extracts from his journals, as in 

 the volumes for 1853 (pp. 3726, 3801, 3841, 3897, 4113) ; 1854 

 (pp. 4200, 4318, 4397) ; 1855 (pp. 4549, 4800) ; 1856 (p. 5012) ; 

 1857 (pp. 5557, 5657, 5725), and 1858 (p. 6160) ; and these may 

 be said to have paved the way for the preparation of the compre- 

 hensive work which he prepared on his return, ' The Naturalist 

 on the Amazons,' published in 1863. We have only to turn to 

 this to discover the nature and extent of the services rendered by 

 Bates to zoological science, more especially in the department of 

 entomology. The collections of insects which he formed and 

 sent home were enormous. During one excursion only, of five 

 months, to St. Paolo he collected more than 5000 specimens, 

 amongst which were 686 new species of all orders, and 79 new 

 species of diurnal Lepidoptera ! 



Mr. Bates, however, cannot be regarded as a mere collector. 

 He was a philosophic naturalist of the first rank, and was the 

 first to enunciate the theory of Mimicry. He observed that 

 butterflies belonging to certain genera were unpalatable to certain 

 birds, and were left untouched by them, while others belonging 

 to genera usually preyed upon by birds were not unfrequently so 

 like the objectionable species as to be mistaken for them. From 

 these facts he formulated the theory that in proportion as the 

 edible species resembled those that were objectionable, they es- 

 caped destruction, and lived to perpetuate their kind. Of these, 

 again, the individuals which most resembled the distasteful 

 species would be the best preserved, until at length so perfect a 



