2 Mr. W. J. Kaye on 
and escape under the guise of the model. To those natur- 
alists who have lived in tropical or subtropical 8. America, 
instances of mimicry between the Syntomidae and Hymeno- 
ptera, Coleoptera, Diptera and others, are constantly 
coming to notice. But very few cases have been figured 
of the models with their mimics. It is to be hoped, there- 
fore, that the present small collection of cases will be useful 
as well as interesting to those who are interested in these 
extraordinary resemblances and the reasons that cause 
them. 
The altered habits of some of the Syntomidae are most 
striking, for when we remember the very different ends 
to be obtained by a 9 wasp and a 2 moth there can be nothing 
really in common. The wasp is predatory and kills all 
sorts of insects to provide food for the resultant larvae 
from the eggs she lays, but the female moth merely lays 
her eggs on a suitable plant or shrub. Any habits, then, 
that the moth has that are wasp-like are certainly not 
directly useful to the species concerned except in the way of 
imitation which quite conceivably deceives its enemies. 
That there is a reason for these resemblances is universally 
admitted, and in the cases of moths being hke various 
species of the Hymenoptera aculeata it is impossible to argue 
that the same environment and general conditions can 
produce habits in moths which are of no use whatever to 
them except as a disguise. But if the moths themselves 
were not hike the wasps one might argue that it was acci-- 
dental that the habits were so alike, but the general appear- 
ance and structure are in conjunction with the habits so 
alike that in the species of Pseudosphex it is impossible to 
distinguish moth from wasp on the flower-heads of Ageratum 
conyzoides unless one is within eighteen inches or so, while 
on the wing at any distance it is quite impossible to dis- 
tinguish them. But while the species of Pseudosphex are 
mimics of the highest degree, vast numbers of other Syn- 
tomidae are only very slightly less perfect in their resem- 
blances and habits. Species of the genus Macrocneme, 
although always distinguishable to an entomologist, are 
wonderfully like members of the genera Salius and Pepsis 
of Pompilid or fossorial wasps. The rapid vibrating of 
the wings, and the waving of the antennae when alighted 
on a leaf or on the ground, is a most noticeable habit in a 
moth, which at once recalls the motions of the Pompilids. 
It should be mentioned also that species of Macrocneme do 
