88 Frederick H. Krecker, 



1887. W. Patten, Studiea on the Eyes of Arthropods. II. Eyes of Acilius 



Journ. of Morph. Vol. II. 

 1894. Fr. Purcell, Über den Bau der Phalangidenaugen. Diese Zeitschr. 



Bd. LVIII. S. 1—53. 

 1900. W. Redikorzew, Untersuchvmgen über den Bau der Ocellen der Insekten. 



Diese Zeitschr. Bd. LXVIII. 4. Heft. S. 581—625. 

 1904 — 05. W. V. Reitzenstein, Untersuchungen über die Entwicklung der 



Stimaügen von Periplaneta orientalis und Cloeon. Zool. Jahrb. Bd. XVI. 



S. 161—178. 



1867. A. Targioni-Tozzetti, Studii sidle Cocciniglie. Estrato dal Vol. III. delle 



Memorie della Soc. Ital. di Sei. Nat. 



1868. — Degli Studi suUe Cocciniglie. Estr. dal N. Cimento T. XXVII. Fase. 



di Febbr. e Marzo. 



Explanation of the figures. 



ax, axial portion of the visual rod; 

 hm, basement membrane enclosing the 



eye; 

 ht, basal thickening of the visual rod ; 

 c, corneal hypodermis; 

 cg, cerebral ganglion; 

 eh., chitin; 



et, connective tissue; 

 da, dorsal accessory eye; 

 de, dorsal eye (accessory); 

 dn, nerve to the dorsal accessory; 

 et, entrance of the nerve to the cerebral 



ganglion ; 

 jf, fleshy Papilla; 

 g, groove surrounding the base of the 



lens; 

 ga, ganglion cell; 

 gn, ganglion cell; 

 li, hypodermis; 



ho, homlike projection of the lens; 

 ht, hypodermal thickening from which 



the eye develops; 



i, ins; 



Z, lens; 



mn, nucleus of the basement mem- 

 brane ; 



n, nerve; 



nc, nucleus of the corneal hypodermis; 



nf, nerve fibrils; 



ns, neural sheath; 



0, Oesophagus; 



p, primary eye; 



"pg, pigment; 



fh, phagocytic cells; 



r, retina; 



s, seam separating the visual rods; 



sc, sheath cells about the developing 

 nerve ; 



va, ventral accessory eye; 



ve, ventral eye (accessory); 



vg, zentral ganglion; 



vn, nerve to the ventral accessory eye; 



vr, Visual rods. 



Plate IV. 



Except where otherwise stated the figures have been dravra by the aid of 

 a Zeiss Camera lucida, using Zeiss compensating ocular 12, 2 mm oü Immersion 

 objective, and a tube length of 160. 



Fig. 1. An outline drawing of the ventral surface of the head to show the 

 Position of the ventral accessory and the primary eyes. Drawn with a dissecting 

 microscope. 



