STRUCTURE, DEVELOPMENT, AND BIONOMICS OF HOUSE-FLY. 541 
EXPLANATION OF PLATES 30—383, 
Illustrating Mr. C. Gordon Hewitt’s paper on “The Structure, 
Development, and Bionomics of the House-fly Musca 
domestica, Linn. Part II. The Breeding Habits 
Development and the Anatomy of the Larva.” 
PLATE 30. 
Fic. 1.—Eges of M. domestica, x 40, dorsal and dorso-lateral views. 
a. Anterior end. 
Fie. 2.—Ege immediately before emergence of the larva which can be seen 
through the dorsal split of the chorion through which it emerges. 
Fic. 3.—Posterior end of mature larva (3rd instar). 
an. Anus. p.sp. Posterior spiracle. 
Fie. 4.—Cephalopharyngeal skeleton of mature larva, left lateral aspect. 
d.p.s. Dorsal pharyngeal sclerite. d.s. Dentate sclerite, 4.s. Hypostomal 
sclerite. ¢.p. Lateral pharyngeal sclerite or plate, deeply incised posteriorly 
to form dorsal and ventral processes. m.s. Mandibular sclerite. 
Fra. 5.—Mature larva of M. domestica. 
a.sp. Anterior spiracular process. az.d. Anal lobe. sp. Spiniferous pad. 
I-XIII. Body segments. 
Fic. 6.—Ventral aspect of the Pseudocephalon and second body segment 
of the mature larva showing the two oral lobes traversed by the food channels. 
1, Lingual-like process. m. Mouth. m.s. Mandibular sclerite. o.¢. Ante- 
rior optic tubercle. 
Fic. 7.—Transverse section through two of the papille of the anterior 
spiracular process to show the clear central lumen. 
e.p. The cuticular processes. 
Fie. 8.—Larva shortly after hatching (1st instar). 
m.s. Mandibular sclerite. p.sp. Posterior spiracle raised on short tubercle. 
sp. Spiniferous pad. 
Fic. 9.—Lateral (left) aspect of the anterior end of the mature larva. 
I-IV. Body segments. a.sp. Anterior spiracular process showing seven 
spiracular papillae. m.s. Mandibular sclerite. 0.¢. Optic tubercle. ps. Pseudo- 
cephalon, 
