Predaceous Insects and their Prey. 373 
gards Rhopalocera the preference is even more marked 
than this comparison suggests ; for some and perhaps all the 
butterflies seized by uncaptured Asilids were probably the 
prey of Alcimus. The species of this genus stand out as 
by far the most important of the Asilid foes of butter‘lies, 
and the study of the habits of the group is especially 
commended to those who believe that all Asz/idx are indis- 
criminate in their attacks on insects. The preference for 
Lepidoptera manifested in common by these genera is an 
interesting example of the support which a purely struc- 
tural foundation for affinity may receive from the study of 
instincts, themselves the outcome of structure in the central 
nervous system. 
As regards mimicry the remarkably long-bodied species 
of these three genera are perhaps protected by a vague 
resemblance to the more slender Hymenoptera—Parasitic 
or Aculeate—but, as the above analysis shows, they have 
not been hitherto observed with victims belonging to this 
Order. 
Philonicus (two species), Nos. 141-147.—So far as the 
insufficient evidence justifies any conclusion this genus 
appears chiefly to attack Diptera (6 examples), although a 
single Tineid victim is also recorded. 
Pamponerus germanicus (No, 148).—The single example 
—a Melolonthid beetle—does not Justify conclusions as to 
the preferences of this species. 
Asilus crabroniformis (Nos. 149-156).—Considering the 
abundance and conspicuous appearance of this fine insect 
the records of prey are somewhat scanty. I am myself 
familiar with the species in several localities but have 
only once seen it with prey—a beetle (No. 150). The 
other tabulated instances, including 35 different grass- 
hoppers, indicate a preference for Orthoptera and Diptera. 
The four recorded examples of the latter Order belong to 
four different families or sub-families—Asilide, Syrphide, 
Sarcophaging and Muscine. <Asilus crabroniformis “ recalls 
in a general way the type of Aculeate colouring and 
pattern which is commonest and most conspicuous in its 
region” *—especially the black and yellow banded appear- 
ance of the most abundant Palearctic species of Vespa. 
At the same, time I have been unable to find a single 
example of an attack by this species upon Hymenoptera. 
* Trans, Ent. Soc, Lond, 1904, p. 662. 
