Entomology : with special reference to its biological and economic aspects . Embryo of CEcanthus, ventralaspect. a, antenna; a^-a^, ab-dominal appendages; e, end ofabdomen; /, labrum; //, leftfundament of labium; Ip, labialpalpus; P~P, thoracic legs; m,mandible; mp, maxillary palpus;mx, maxilla; p, procephalic lobe;pr, proctodaeum.—After Ayers. Then follow the three thoracic gan- glia and ten (usually) abdominalganglia. The first three neuro-meres always unite together toform the brain, and the next four(always three; but four in Col-lembola and perhaps other insects), to form the suboeso-phag
Entomology : with special reference to its biological and economic aspects . Embryo of CEcanthus, ventralaspect. a, antenna; a^-a^, ab-dominal appendages; e, end ofabdomen; /, labrum; //, leftfundament of labium; Ip, labialpalpus; P~P, thoracic legs; m,mandible; mp, maxillary palpus;mx, maxilla; p, procephalic lobe;pr, proctodaeum.—After Ayers. Then follow the three thoracic gan- glia and ten (usually) abdominalganglia. The first three neuro-meres always unite together toform the brain, and the next four(always three; but four in Col-lembola and perhaps other insects), to form the suboeso-phageal ganglion. Compound ganglia are frequently formedalso in the thorax and abdomen by the union of primitiveganglia. DEVELOPMENT 153 Tracheae.—The trachere begin as paired invaginations ofthe ectoderm (Fig. 201, f) ; these simple pockets elongate and Fig. Diagrammatic sagittal sections to illustrate invagination of germ band in Calop-teryx. a, anterior pole; ac, amnion cavity; am, amnion; b, blastoderm; d, dorsal;g, germ band; h, head end of germ band; p, posterior pole; s, serosa; v, ventral; y,yolk.—After Brandt. Fig. 198.
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectentomology, bookyear1
