XX 
WARNING COLORATION AND MIMICRY 
249 
while the larva is of protective colours, and therefore almost 
certainly edible. A much more abundant moth, of about the 
same size and appearing about the same time, is Spilosoma 
menthrasti, also white, but in this case both it and its larva 
have been proved to be inedible. The white colour of the 
female Diaphora, although it must be very conspicuous at 
night, may, therefore, have been acquired in order to re¬ 
semble the uneatable Spilosoma, and thus gain some pro¬ 
tection. 1 
Mimicry among Protected ( Uneatable ) Genera. 
Before giving some account of the numerous other cases 
of warning colours and of mimicry that occur in the animal 
kingdom, it will be well to notice a curious phenomenon 
which long puzzled entomologists, but which has at length 
received a satisfactory explanation. 
AYe have hitherto considered, that mimicry could only occur 
when a comparatively scarce and much persecuted species 
obtained protection by its close external resemblance to a 
much more abundant uneatable species inhabiting its own dis¬ 
trict ; and this rule undoubtedly prevails among the great 
majority of mimicking species all over the world. But Mr. 
Bates also found a number of pairs of species of different genera 
of Heliconidse, which resembled each other quite as closely as 
did the other mimicking species he has described ; and since 
all these insects appear to be equally protected by their in¬ 
edibility, and to be equally free from persecution, it was not 
easy to see why this curious resemblance existed, or how it 
had been brought about. That it is not due to close affinity 
is shown by the fact that the resemblance occurs most fre¬ 
quently between the two distinct sub-families into which (as 
Mr. Bates first pointed out) the Heliconidse are naturally 
divided on account of very important structural differences. 
One of these sub-families (the true Heliconinm) consists of two 
genera only, Heliconius and Eueides, the other (the Danaoid 
Heliconinse) of no less than sixteen genera; and, in the in¬ 
stances of mimicry we are now discussing, one of the pairs or 
1 Professor Meldola informs me that he has recorded another case of 
mimicry among British moths, in which Acidalia subsericata imitates Asthena 
candidata. See Ent. Mo. Mag., vol. iv. p. 163. 
