59 
tera exist merely by mistaken identity are, in Guiana, wonderfully 
numerous. Frequently I found myself taking something altogether 
different from what I thought it to be. One of the most interesting 
cases that came under my notice was an instance of three groups 
being involved— -viz., Erycinidae, Ithomiinae of the Nymphalidae, and 
the Hypsidae. Two different families of butterflies and one of moths. 
I do not think there is any reason to believe that any of these species 
are palatable. It is probably a Mullerian group, one of the species 
having been dominant. From the relative abundance of one to an¬ 
other, the moth would be more influential, as being in much greater 
abundance than either of the two butterflies. It is remarkable that a 
species of Stalactis, viz., satellites, exists on the Upper Amazons that 
exactly resembles this moth Lauron partita, but apparently does not 
occur in Guiana. I feel considerable doubt in my own mind if true 
Batesian mimicry exists. Are some species really so palatable to 
birds, etc., that were they not similar in colouring to other distasteful 
species they would become exterminated ? The accumulating evidence 
goes to disprove it: (1) the so-called mimicked species is often fat- 
more numerous than the mimicker—a state of affairs that would give 
little protection to a persecuted species ; (2) the so-called mimicked 
species are attacked just as much as the so-called mimicking species. 
It appears, therefore, to matter little to an insect whether it be palat¬ 
able or not. If it is like one or more other insects the attacks will be 
shared, roughly, in proportion to the abundance of each. The “ pro¬ 
portions ” have not been hitherto much considered, but they must be 
of the utmost importance in the competition. 
After the first day at the Potaro station it rained, on and 
off, the whole time, and as it was now the middle of May I 
had to expect bad weather. In the West Indian islands and in 
Georgetown the sun generally appears immediately after a heavy 
shower, but in the depths of the forest, as one is on the Potaro, 
especially in the low, swampy parts, the sun sometimes does not 
show itself for days at a time, and collecting is very seriously 
interrupted. The interruption at last became so constant that I de¬ 
cided to work my way back to town, and thence go to Trinidad again, 
where I knew the sun was more obliging. As in coming, I broke the 
twelve jolty miles to the waterside at the eight-mile house, this time 
for two days, and during the time my kind host (Mr. C. B. Roberts) 
became so interested that he said he would collect for me, with what 
splendid results you will be able to judge for yourselves. I decided, 
when the time came, to walk to the waterside instead of driving, and 
the decision was repaid. Morphos, of how many species I don’t know, 
swarmed, but Morpho hecuba, M. adonis, and M. menelaus were there 
for certain. M. adonis had not been seen before, but was now abun¬ 
dant. A single specimen only was caught, and as it has a large piece 
out of one of its wings, that probably explains how it came within 
striking distance, its flight having been enfeebled thereby. One of the 
most splendid Theclids, Evenus nobilis, was then taken, and the pro¬ 
verbial last day being the best, nearly, if not quite came true. 
Gentlemen, there are many things I have not told you about. I 
have sketched the expedition up till the beginning of the return 
journey from the Potaro, and think this a fitting point to leave you, 
as up till now the fell fiend malaria had not interfered with the 
enjoyment of the trip. Soon after this I found I was not to escape, 
