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STRUCTURE, DEVELOPMENT, AND BIONOMICS OF HOUSE-FLY. '541 



EXPLANATION OF PLATES 3033, 



Illustrating Mr. C. G-ordon Hewitt's paper on " The Structure, 

 Development, and Bionomics of the House-fly Musca 

 domestic a, Linn. Part II. The Breeding Habits 

 Development and the Anatomy of the Larva." 



PLATE 30. 



FIG. 1. Eggs of M. domestica, x 40, dorsal and dorso-lateral views. 

 a. Anterior end. 



EIG. 2. Egg immediately before emergence of the larva which can be seen 

 through the dorsal split of the chorion through which it emerges. 



EIG. 3. Posterior end of mature larva (3rd instar). 

 an. Anus. p.sp. Posterior spiracle. 



PIG. 4. Cephalopharyngeal skeleton of mature larva, left lateral aspect. 



d.p.s. Dorsal pharyngeal sclerite. d.s. Dentate sclerite, h.s. Hypostomal 

 sclerite. l.p. Lateral pharyrigeal sclerite or plate, deeply incised posteriorly 

 to form dorsal and ventral processes, m.s. Mandibular sclerite. 



FIG. 5. Mature larva of M. domestica. 



a.sp. Anterior spiracular process, an. I. Anal lobe. sp. Spiniferous pad. 

 I-XIII. Body segments. 



FIG. 6. Ventral aspect of the Pseudocephalon and second body segment 

 of the mature larva showing the two oral lobes traversed by the food channels. 



/. Lingual-like process, m. Mouth, m.s. Maudibular sclerite. o.t. Ante- 

 rior optic tubercle. 



FIG. 7. Transverse section through two of the papillae of the anterior 

 spiracular process to show the clear central lumen. 



c.p. The cuticular processes. 



FIG. 8. Larva shortly after hatching (1st instar). 



m.s. Mandibular sclerite. p.sp. Posterior spiracle raised on short tubercle. 

 sp. Spiniferous pad. 



FIG. 9. Lateral (left) aspect of the anterior end of the mature larva. 

 I-IV. Body segments, a.sp. Anterior spiracular process showing seven 

 spiracular papillse. m.s. Mandibular sclerite. o.t. Optic tubercle, ps. Pseudo- 



ephalon. 

 c 



