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 AsiUds were probably the 

 prey of Alcirmis. The species of this genus stand out as 

 by far the most important of the AsiUd foes of butterflies, 

 and the study of the habits of the group is especially 

 commended to those who believe that all Asilidie 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. 



PMlonicus (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. 



Pamponcrus germanicus (No, 148). — The single example 

 — a Melolonthid beetle — does not justify conclusions as to 

 the preferences of this species. 



Asilus crahroniformis (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 3 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 — Asilidm, Syrphidc'B, 

 Sarcophagina3 and 3fusciniB. Asilus crahroniformis " 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 Palsearctic 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. Eut. Soc. Lond. 1904, ^. 662. 



