. Class book of economic entomology. Insects, Injurious and beneficial. [from old catalog]; Insects; Insects. 20 ECONOMIC ENTOMOLOGY bring about the contraction and expansion of the abdomen necessary for respiration. In the thorax of larval insects and of the wingless forms the arrange- ment of muscles follows the same general plan as in the abdomen, but the presence of the leg muscles makes it more complicated (Fig. 27). In the winged insects, however, this primitive arrangement cannot be readily recognized owing to the presence of large wing muscles and also to the fact that the thoracic seg
. Class book of economic entomology. Insects, Injurious and beneficial. [from old catalog]; Insects; Insects. 20 ECONOMIC ENTOMOLOGY bring about the contraction and expansion of the abdomen necessary for respiration. In the thorax of larval insects and of the wingless forms the arrange- ment of muscles follows the same general plan as in the abdomen, but the presence of the leg muscles makes it more complicated (Fig. 27). In the winged insects, however, this primitive arrangement cannot be readily recognized owing to the presence of large wing muscles and also to the fact that the thoracic segments are very often fused together. The muscles which move the head originate in the prothorax and are inserted into the base of the head. Within the head are muscles. Fig. 25.—Internal organs of the cricket {Gryllus pennsylvanicus). AN., Anten- nal nerve; Oes., oesophagus; Br., brain; T., teutorium; Ao., aorta; 5., suspensorium of ovary; H., heart; Ov., right ovary; Col., colon; JR., rectum; A., anus; MT., Mal- pighian tubules; Od., oviduct; Op., ovipositor; BC, bursa copulatrix (copulatory pouch); Vag., vagina; RS., receptaculum seminalis; Mes., mesenteron; VC, con- nectives of ventral nerve chain; VG., ganglia of ventral nerve chain; , salivary glands; , labial nerve; SG., subcesophageal ganglion; , mandibular nerve; SD., salivary duct; HP., hypopharynx; P., pharynx; , maxillary nerve; LN., labial nerve; ON., optic nerve; C, crop; P., proventriculus; GC., gastric caeca. for the control of the mouth-parts and antennas. In the mandibulate insects the muscles which move the mandibles occupy the greater part of the head cavity. Mention should also be made of the alary muscles of the heart, the circular and longitudinal muscles of the digestive canal, and the spiracular muscles which bring about the closure of the spiracles during respiration. A muscle consists of a bundle of long fibres, each with several nuclei and a sheath, the sarcolemma. In most cases t
Size: 2581px × 968px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, booksubjectinsects, bookyear1919
