Entomology : with special reference to its biological and economic aspects . e anterior of these two, whichjoins the sternum, is termed thecpistcnium; the other, the epi-nicroji. The former is dividedinto two sclerites in Odonata andboth are so divided in sternum, though usuallya single plate, is in some in-stances divided into halves, asin the cockroach, or even intofive sclerites (Forficulid?e).To these should be added the a pairof erectile appendages of theprothorax; and the paraptem, or tcgulcc, of Lepidoptera andHymenoptera—a pair of small sclerites at the bases of thefront
Entomology : with special reference to its biological and economic aspects . e anterior of these two, whichjoins the sternum, is termed thecpistcnium; the other, the epi-nicroji. The former is dividedinto two sclerites in Odonata andboth are so divided in sternum, though usuallya single plate, is in some in-stances divided into halves, asin the cockroach, or even intofive sclerites (Forficulid?e).To these should be added the a pairof erectile appendages of theprothorax; and the paraptem, or tcgulcc, of Lepidoptera andHymenoptera—a pair of small sclerites at the bases of thefront wings. Each thoracic segment bears a pair of spiracles in the em-bryo and in some adults as well (Campodea, Heteroptera),but in most imagines there are only two pairs of thoracicspiracles, the suppressed pair being usually the prothoracic. The sclerites of the thorax owe their origin probably tolocal strains on the integument, brought about by the musclesof the thorax. Thus the primitively wingless Thysanura andCollembola have no hard thoracic sclerites, though certain. Dorsal aspect of the thorax of abeetle, Hydrous piceus. i, pronotum;2, mesopraescutum; 3, mesoscutuin; 4,mesoscutellum; 5, mesopostscutellum;6, metaprsescutum; 7, metascutum; S,metascutellum; 9, metapostscutellum. pQtagia of LepidoptCra—After Newport. ANATOMY AND PHYSIOLOGY 49 creases about the bases of the legs may be regarded as incipi-ent sutures, produced mechanically by the movements of the Fig. s8.
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectentomology, bookyear1
