66 C. HERBERT HURST. 



they grow till they occupy the greater part of the surface of the 

 head. 



So much has of late been written upon the eyes of insects, that 

 one should hesitate to add to that literature without having made 

 very special study of the organs in question. Still, one of the most 

 remarkable papers of the day (Patten, 11) has attracted so much 

 attention, and is so strongly opposed to the views of previous 

 observers, that the little I have already observed may be of interest. 



Each eye is made up of a very large number of " elements." 

 Growth of the eye consists in the addition of new " elements " at 

 its edge. Each new element is formed directly from the previously 

 unmodified epidermis at the margin of the eye, and each arises 

 independently of the rest of the eye, as a separate invagination of 

 the epidermis. The cells, four in number, around the margin of 

 each invagination, persist as the " nuclei of Semper," " corneal hypo- 

 dermis," "corneal epidermis," " cellules cristallines," "cellules de 

 Semper," " refractive globules " or " spherules." The invaginated 

 portion gives rise to all the other parts lying outside the limiting 

 membrane, with the possible exception of the pigment cells. The 

 elements are at first devoid of pigment. 



The details of the development I have not yet worked out, and I 

 think it best to reserve further description for a future paper. 



Other sense-organs developed during pupal life are antenna. 

 Antennae are, it is true, present already in the larva, but they have 

 no resemblance to those of the imago, and they are functionless 

 during pupal life. 



The epidermis round the base of each antenna of the larva grows 

 rapidly, and as it is prevented, by the rigid and unyielding cuticle 

 of the shaft of the antenna, from growing forwards, it grows back- 

 wards, and becomes "telescoped" and much folded, and sections 

 through the larva show that the differentiation of the epidermis of 

 the different parts has already begun. 



When the pupa escapes from -the larval cuticle, much of the 

 folding is undone, but a portion of the telescoping persists at the 

 base of the organ, and this part gives rise to the large hemispherical 

 basal joint of the antenna of the imago. 



This remarkable organ was described in the imago thirty-five 

 years ago by Johnston (13), but very imperfectly. Externally it is 



