112 MIMICRY, AND OTHER PROTECTIVE 
though it is never perhaps quite equal to that of the 
female. In insects the case is very different; they 
pair but once in their lives, and the prolonged existence 
of the ‘male is in most’ cases quite unnecessary for the 
continuance of the race. The female, however, must 
continue to exist long enough to deposit her eggs in a 
place adapted for the development and growth of the 
progeny. Hence there is a wide difference in the need 
for protection in the two sexes; and we should, there- 
fore, expect to find that in some cases the special pro- 
tection given to the female was in the male less in 
amount or altogether wanting. The facts entirely con- 
firm this expectation. In the spectre insects (Phas- 
mid) it is often the females alone that so strikingly 
resemble leaves, while the males show only a rude 
approximation. The male Diadema misippus is a very 
handsome and conspicuous butterfly, without a sign of 
protective or imitative colouring, while the female is 
entirely unlike her partner, and is one of the most 
wonderful cases of mimicry on record, resembling 
most accurately the common Danais chrysippus, in 
whose company it is often found. So in several speciesi 
of South American Pieris, the males are white and 
black, of a similar type of colouring to our own 
“cabbage” butterflies, while the females are rich 
yellow and buff, spotted and marked so as exactly to 
resemble species of Heliconide with which they asso- 
ciate in the forest. In the Malay archipelago is found 
a Diadema which had always been considered a male 
insect on account of its glossy metallic-blue tints, 
