a few Observations in Mimicry. 7 
morning) neither show a disposition to fly, but are extremely 
sluggish. 
Fig. 12 of Pterygopterus caeruleus with fig. 12a of the 
Pompilid wasp Salius kirby affords a striking case of 
Batesian mimicry. The very dark blue-black wings with 
the smallest amount of lustre, the conspicuous yellow 
antennae and the long hind-legs of the fossor are most 
completely copied in the 9 Syntomid moth. Both fly 
together in the forest near the Potaro River above the 
Tumatumari cataract in Central British Guiana. The 
wasp is common and flies heavily, carrying its antennae 
and hind-legs almost as shown in the figure. The first and 
second pairs of legs are carried more folded to the abdomen. 
The moth is a rare species, and only the one specimen was 
taken by Mr. C. B. Roberts, who was collecting in the same 
locality for six years. I am unable to say anything as to 
its habits, but it is highly probable that it carries its long 
hind-legs stretched out behind in the way the wasp does, 
in the same way as members of the genus Macrocneme do, 
and as is shown in the case figured of Macrocneme adonis 
(fig. 13). 
Tig 13 and 13a is another case of a Syntomid moth 
mimicking a Pompilid wasp. In this instance the two 
insects, Macrocneme adonis (fig. 13), Pepsis (fig. 13a), 
occur together towards the end of May in the wooded 
ravines at about 3,500 ft. on the coast range of mountains 
at Caracas, Venezuela. Flying at the same time is another 
species of Syntomid Macrocneme lades (fig. 14). In some 
hghts this species looks very much like the Salius even in 
the cabinet drawer, while in flight it is almost as much like 
the wasp as M. adonis. When the sunlight falls on the 
wings of the wasp M. adonis is the better mimic, but in 
shade Macrocneme lades and Macrocneme adonis are hardly 
distinguishable, and both are equally good mimics. The 
habits of these Macrocneme species are extremely interest- 
ing. They carry their hind-legs extended in imitation of 
the wasp. They alight on leaves or settle on the ground, 
and do not frequent flowers. When settled on a leaf they 
vibrate their wings while in the position as is shown in 
fig. 14. They also wave their antennae, all of which are 
characters of the “ marabunta’”’ as these wasps of the genus 
Salwus are invariably called locally. Fig. 14 is a specimen 
of M. lades from S. Brazil, and it was drawn purposely to 
show the position in which the species alights with the wide 
