. Outlines of zoology. Zoology. COCKROACH. 291 The young are. Fig. 127.—Leg of cockroach. , Broad expanded coxa; tr., troch- anter ;yC, femur ; //., tibia; ta., five- jointed tarsus with terminal claws and adhesive cushions. same order as locusts and grasshoppers, hatched as miniature adults, except that wings are absent; in other words, there is no metamorphosis in develop- ment. Skin.—There is an exter- nal chitinous cuticle and a subjacent cellular layer—the epidermis or hypodermis— from which the cuticle is formed. The newly hatched cockroaches are white, the adults are dark brown. Moultin
. Outlines of zoology. Zoology. COCKROACH. 291 The young are. Fig. 127.—Leg of cockroach. , Broad expanded coxa; tr., troch- anter ;yC, femur ; //., tibia; ta., five- jointed tarsus with terminal claws and adhesive cushions. same order as locusts and grasshoppers, hatched as miniature adults, except that wings are absent; in other words, there is no metamorphosis in develop- ment. Skin.—There is an exter- nal chitinous cuticle and a subjacent cellular layer—the epidermis or hypodermis— from which the cuticle is formed. The newly hatched cockroaches are white, the adults are dark brown. Moulting, which involves a casting of the cuticle, of the internal lining of the tracheae, etc., occurs some seven times before the cockroach attains in its fifth year to maturity. The muscles which move the appendages, and produce the abdo- minal movements essen- tial to respiration, are markedly cross striped. Nervous system.—A pair of supra-cesopha- geal or cerebral ganglia lie united in the head. As a brain they receive impressions by anten- nary and optic nerves. By means of a paired commissure surround- ing the gullet, they are connected with a double ventral chain of ten ganglia. Of these, the first or sub-cesopha- geal pair are large, and give off nerves to the mouth parts, etc.; from each of the ganglia of the thorax and the abdomen nerves are given off. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Thomson, J. Arthur (John Arthur), 1861-1933. Edinburgh, Glasgow and London, H. Frowde and Hodder & Stoughton
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Keywords: ., bookauthorth, bookcentury1800, bookdecade1890, booksubjectzoology
