. The anatomy, physiology, morphology and development of the blow-fly (Calliphora erythrocephala.) A study in the comparative anatomy and morphology of insects; with plates and illustrations executed directly from the drawings of the author;. Blowflies. 258 THE EMBRYOLOGY OF THE BLOW-FLY IN THE EGG. at the same time sulci appear in the epiblast, separating the larval segments. The fore-head and procephalic lobes rapidly disappear, and the rudimentary cephalic appendages undergo the following modifications. The anterior pair disappear. According to Weismann, they approach each other and form a
. The anatomy, physiology, morphology and development of the blow-fly (Calliphora erythrocephala.) A study in the comparative anatomy and morphology of insects; with plates and illustrations executed directly from the drawings of the author;. Blowflies. 258 THE EMBRYOLOGY OF THE BLOW-FLY IN THE EGG. at the same time sulci appear in the epiblast, separating the larval segments. The fore-head and procephalic lobes rapidly disappear, and the rudimentary cephalic appendages undergo the following modifications. The anterior pair disappear. According to Weismann, they approach each other and form a median outgrowth in the anterior wall of the stomodaeum. On. Fk;. 43.—The anterior extremity of the Hlow-fly eml)ryo in five successive stages, showing the transformation of the mouth organs : /, a side view of the head of the embryo before the segmentation of the coelomic plates, after Weismann ; 2, a later stage of the same ; $ and 4, still later stages ; j, a ventral view of the head in the same stage ; (5, a ventral view of the head in the mature embryo ready to escape from the egg. the same authority the median tooth of the larval mouth armature represents their remains, and is therefore composed of the united mandibles. I am by no means sure that such is its origin, and, as already stated, regard it as the labrum. The second pair of appendages, the maxillae, become parallel with each other, and form the maxillae of the larva. The third pair Descrii'tion of XV. Two sections through the head of an embryo during the involution of the head discs (procephalic lobes). Fk; I.—A section through the fore-head and maxillse : //;, the fore-head, showing the rudimentary brain and brain vesicles, v ; the single layer of cells enclosing the vesicles, probably becomes the retinal disc ; the cleft, inin, is the orifice of the stomodxum ; iiix, the maxilla ; r', the maxillary disc ; s g, salivary duct. The cellular mass, i\ is probably part of the rudimentary pharynx. Flc.
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