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XVIII. On the Ocelli in the Genus Anthophorabia. 

 By George Newport, Esq., F.B.S., F.L.S. 8fc. . 



Read April 19, 1853. 



oINCE the publication of my observations on the genus Anthophorabia, in the Transac- 

 tions of the Society*, my attention has again been directed to the peculiarities exhibited 

 by the principal organs of sense, and to the differences which exist in the comparative 

 anatomy of these structures, the eyes, in the two sexes of insects of this genus. I now 

 propose to offer a few remarks on the nature of these differences, in accordance with 

 certain well-established laws in the anatomy and development of animals, and in extension 

 of views which I have already begun to elucidate in the memoirs I have had the pleasure 

 of communicating to this Society on the anatomy and development of Meloe. 



On a former occasion! I pointed out the curious circumstance that the male individuals 

 of this genus have ocelli at the sides of the head, instead of the large compound eyes which 

 exist in the females, and other Hymenoptera, and that they have also three ocelli on 

 the vertex. The existence of lateral ocelli in Anthophorabia, at precisely similar parts of 

 the head as the compound eyes and ocelli in other insects, is incontrovertible, and yet it 

 has been denied. It is equally certain that these structures, as I shall endeavour to show, 

 are true representatives of organs of vision ; and that, imperfect as they are, they are good 

 generic distinctions. 



The appearance which they exhibit under the microscope is, indeed, such as might 

 readily induce those who are imperfectly acquainted with the laws of structural anatomy 

 to regard them as merely coloured portions of the surface of the head, and not as ocelli, 

 or organs of vision in any stage of development ; and such observers might feel themselves 

 supported in this opinion by the circumstance that there are also appearances on the 

 cephalo-thorax of certain species of Arachnida, in the precise situation of ocelli in other 

 species, which, by some, are regarded as mere spots or markings of the tegument, and not 

 as the representatives of eyes. 



This opinion would be fully entitled to respect, so long as its authors maintained it as 

 an opinion, and made no attempt to enforce it in opposition to principles which are sus- 

 ceptible of demonstration, or to support it by supposed analogies. 



To judge aright of the nature of the lateral ocelli, in the male Anthophorabia, we must 

 not only remember that they correspond precisely, in situation, to the eyes in the female, 

 but must also call to mind what are the essential conditions of a structure which is spe- 

 cially destined for the appreciation of light. 



Professor Owen has stated % that the lowest form of this structure in Fishes is — 



* Vol. xxi. pp. 63 & 79. t Loc. tit. p. 64. t. 8. figs. 1 & 4. J Lectures, p. 202, 1846. 



