Hymeno^tera aculeata from Majorca and Spain. 663 



remarkable likeness to such common insects should convey 

 an impression of extreme rarity and lead to a want of 

 knowledge as to habits. Asilid mimicry of this latter 

 kind may be exactly paralleled by resemblances such 

 as that of the Histerid f^anrinus virescens to its distasteful 

 Piiytophagous prey, Fh/i'don cochleari/&, — following the 

 convincing interpretation offered by Mr. Horace Donis- 

 thorpe (Trans. Ent. Soc. Lond., 1901, p. 854). 



The resemblance of the Volucellas for the Aculeates 

 has probably been brought about in a slightly different way, 

 although here too the older interpretation of the mimicry 

 as aggressive must, I believe, be abandoned. My friend Dr. 

 W. Hatchett Jackson has recently presented to the Hope 

 Department a specimen of Volucella inanis, which he 

 captured on August 29, 1903, close to the entrance of a 

 wasps' nest in his garden at Pen Wartha, Weston-super- 

 Mare. The wasps paid not the slightest attention to it, 

 although they instantly attacked other insects venturing 

 near the opening. Considering that wasps will detect 

 and kill the individuals from other communities, it is 

 most improbable that they were deceived by the appearance 

 of the Volucella. Furthermore, Dr. Jackson has had the 

 opportunity of studying M. Fabre's latest volume, and 

 informs me that the great observer believes V. inanis to be 

 a beneficial guest in the wasps' nest, feeding on debris, 

 waste substances, excreta, etc. He also states that the 

 larvae of these diptera are not attacked even when upon 

 the combs of the wasp. These results entirely accord 

 with observations upon V. hombylans carried out by the 

 present writer in association with Miss Cora B. Sanders 

 early in July 1898. Fresh and active specimens of the 

 Volucella were lightly but securely girdled with a fine 

 silken thread, the other end being attached to a long 

 slender twig. In this way it was possible to guide the 

 movements of the fly and compel it to wander close to the 

 opening of the underground nest of Bombus terrestris, and 

 even to enter the passage. Examples of both the red-tailed 

 form of V. hombylans and the banded form (var. mystacea) 

 were thus tested, and only once was any antagonism dis- 

 played. On this occasion the Vohccella was made to 

 descend the passage, and thus met an ascending worker. 

 The humble-bee grappled with the fly, wrestled with it in 

 a clumsy manner for a few seconds, and then left it 

 apparently without having caused any injury. We also 



