Practice question

Insect thorax comprises three segments prothorax, mesothorax and metathorax, each originating one pair of jointed legs, thus hexapod condition totals six legs universally diagnostic for Insecta or Hexapoda. Leg segmentation includes coxa, trochanter, femur, tibia, tarsomeres with claws, variably modified for running, jumping as in saltatorial orthopterans, grasping or digging. Wing articulation occurs dorsally on meso- and metathorax in winged pterygotes. Sternal, pleural and tergal sclerites anchor powerful flight and leg muscles. Six-legged thoracic arrangement differentiates insects from eight-legged arachnids and multi-legged myriapods, fundamental for entomology.