ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 433 



Structure and Development of the Compound Eye of the Honey 

 Bee.* — E. P. Phillips has made a careful study of this, and comes to the 

 following conclusions. The primitive arrangement of the ommatidia is 

 tetragonal. The hairs over the lens are secreted by bi-nucleated hair- 

 cells, with intracellular ducts, which lie between the ommatidia. The 

 ommatidium arises as a group of cells with superimposed nuclei, which 

 later become arranged as a spindle surrounded by smaller cells. This 

 spindle is the retinula, and the cone cells and pigment cells assume a 

 distal position by a morphological invagination. 



The retinula is the centre of the ommatidium, and the cone cells, 

 corneal pigment cells and outer pigment cells, follow in the order named. 

 The ommatidium is composed of eight or nine retinular cells around 

 the rhabdome, four cone cells, two corneal pigment cells, and about 

 twelve outer pigment cells. 



The rhabdome and cone are intracellular secretions, while the lens is 

 an extracellular secretion of the pigment cells. The corneal pigment 

 cells are homologous with the corneal hypodermal cells of crustacean and 

 apterygote ommatidia. The innervation of the ommatidium is by a 

 differentiation of part of the retinular cells into nerve fibrils, and these 

 extend to the retinular ganglia. The lens is secreted by the corneal 

 pigment cells, which early in the pupa stage are distal to the cone, and 

 possibly also by the outer pigment cells. Pigment is formed inside all 

 the cells of the ommatidium, except the cone cells, by a cytoplasmic 

 differentiation. 



The ommatidium arises from a strictly one-layered epidermis, which 

 passes directly from the larva to the pupa without the loss of any cells 

 or additions from other tissues. 



Foot of House-Fly.f — A. A. C. Eliot Merlin describes what is in 

 all probability the orifice from which exudes the viscous fluid which 

 .may be seen adhering to, and often entirely enveloping, the sickle 

 filament. With a magnification of 3200 diameters he discovered an 

 excrescence which protrudes from the side of the sickle just midway 

 between the point and the haft. 



New CEstrid Larva from Hippopotamus.} — K. Griinberg describes 

 Rhiniestrus hippopotami from the cranial cavity of the hippopotamus. It 

 differs chiefly in its spines from Rh. purpureas from the nasal chamber 

 of horse and zebra. 



Metamorphosis of Lebia scapularis.§ — F. Silvestri describes the 

 metamorphosis and habits of this small carabid beetle, which attacks the 

 eggs, larva3, and nymphs of Galerucella luteola. It is remarkable in 

 exhibiting a hypermetaniorphosis — having two well defined larval forms 

 — and it is unique in constructing a silken cocoon which is secreted by 

 the malpighian tubes. 



* Prnc. Acad. Nat. Sci. Philadelphia, 1905, pp. 123-57 (3 pis). 



t Journ. Quekett Micr. Club, 1905, pp. 167-8 (6 figs). 1 ! 



j SB. Ges. Natur. Freuude, Berlin, 1904, pp. 35-9 (2 tigs.). 



§ Redia, ii. (1904) pp. 69-84 (5 pie.). 



Aug. 16th, 1905 2 G 



