Vol. XXXl] ENTOMOLOGICAL NEWS 97 



and also by the scape of the antennae being black above. Rarely the 

 scape is yellow below. 

 Length 8-14 mm. 



Specimens collected at: Beaufort, E. Aup., 1902; June 15 

 and 24, 1903, F. S.; Nags head, L. Aug., 1919, F. S. 9 speci- 

 mens: 5 females, 4 males. 



The Eyes of Insects.* 



By ALEX. D. MAcGnxiVRAY. 



There is always difficulty in differentiating between the 

 kinds of eyes of insects so far as their names are concerned. 

 This becomes especially complicated when it is necessary to 

 compare the eyes of adult insects as those of butterflies or 

 moths with those of their larvae. 



All are agreed in designating the large organs of sight com- 

 posed of several or numerous independent parts as the com- 

 pound eyes or simply as the eyes. But there is a lack of uni- 

 formity, when the names of the parts of a compound eye are 

 considered. The early entomologist designated each of the 

 component parts of a compound eye as an ocellus, plural 

 ocelli. This led to confusion because the simple eyes of in- 

 sects were also designated as ocelli. A compound eye is com- 

 posed of a number of subdivisions, each considered as an in- 

 dependent eye and known as an ommatidium, plural omma- 

 tidia. Each ommatidium consists of an external usually 

 more or less convex hexagonal area of cuticle, the cornea, the 

 crystalline lens or cone, the rhabdome, the retinula cells, the 

 pigment cells, and the nerve connections. Some writers 

 apply the name of ommatidium to one of the entire subdivi- 

 sions of a compound eye and also to the external area of the 

 cuticle. Others have designated each of the hexagonal areas 

 of the cuticle as a facet and applied the name of ommatidium 

 io an entire subdivision of a compound eye only. It is de- 

 sirable that these words should be restricted in their use and 



"Contributions from the Kniomolo;<ir;il Laboratories of the I'niversity 



ol Illinois, \O. 64. 



