Hl/mnwpkra acuhata from Majorca and Spain. 647 



the manner suggested above (Trans. Ent. Soc. 1902, pp. 

 386, 887). 



I cannot doubt that a closer attention to the facts of 

 mimicry in the Aculeates would long ago have revealed 

 the insufficiency of the Batesian hypothesis and the 

 necessity of that to which Fritz M tiller was driven in 

 1870. The group on Montserrat may be compared in the 

 closest manner with the synaposematic Neotropical Rho- 

 palocera. The central species, belonging to the genus 

 Sphecodcs, represent the Ithomiimv, usually the dominant 

 members of the South American groups. The genera 

 Halichis, Nomada, and Osmia, similarly represent the 

 convergent Lycorca, Hcliconius, and Adinotc ; while the 

 fly Ocijptcra may be to some extent paralleled by a Hetero- 

 cerous mimic, such as Pcricopis or Oastnia. 



As regards both groups we may feel the same confidence 

 that the Mullerian explanation of common warning colours 

 accounts for nearly the whole of the facts : as regards both 

 the same uncertainty as to whether some outlying member, 

 such as the fly in one or Gastnia in the other, may not be 

 a real (Pseudaposematic) mimic in the Batesian sense. 

 In both groups the fact lost sight of by Bates is equally 

 evident, viz. that the mimicry is closest between those 

 members whose special defence is clearest — that just as 

 the mimicry of Ithomiine by Heliconine far transcends the 

 resemblance borne to the former by Danaine, Nymphaline, 

 Pierine, or moth, so the likeness of other Aculeate genera for 

 S2)hecodcs far surpasses that borne by the mimetic Dipteron. 

 In fact, Mr, Saunders speaks of the similarity between the 

 females of some of the small southern species of Halidus 

 and Sphecodcs being so great that he has often to look for 

 structural characters at the apex of the abdomen in order 

 to decide upon the genus. In speaking of this remarkable 

 resemblance the great Hymenopterist, indeed, suggests the 

 probability that Halidus and S'phecodes arose from a single 

 stock at no distant date. But, however recent this period 

 may be, it is highly improbable that superficial likeness 

 in colour and pattern can be its heritage, inasmuch as 

 a safe distinction can be established by an appeal to 

 comparatively deep-seated structural characters. 



This interesting group is only a section of a very 

 large assemblage of Aculeates characterized by a black 

 ground-colour, and the development of more or less red 

 on the abdominal segments. Mr. Saunders has kindly 



