282 ARTHROPODS. 



DIAGRAM XIII. 

 Peripatus, Myriopods, and Insects. 



At the base is a diagram of Peripatus, with a nephridium to the right, 

 and a branching trachea to the left. 



Above there is a diagrammatic representation of a simple Mynopod 

 (Myr.), and one of the primitive wingless insects — Campodea (Cam.). 



The diagrammatic figure of an " ideal insect " shows the head with 

 antennae (o»/.), eyes{^.), mouth and mouth-parts (m.p.); the thorax with 

 legs and wings ; the abdomen with stigmata {st. ) ; the dorsal heart 

 (h.); the reproductive organs and ducts (r.); the gut with gullet and 

 salivary glands [s. g. ), crop {cr. ), gizzard {g. ), stomach and digestive 

 C£eca {m. g. ), intestine with Malpighian tubules («. t.), the hind-gut 

 {h. g.), the fatty body (/ b.), the brain (br.), the ring round the gullet, 

 the sub-oesophageal ganglia (gangl.), and the ventral chain are also 

 shown. 



The mouth-parts of the cockroach are shown : — (l) the mandibles 

 {nm.); (2) the first maxillae, with cardo [c), stipes {si.), palp {vix. p.), 

 galea [g.), lacinia (/.) ; (3) the second maxillae, with sub-mentum (s. m.), 

 mentum (»;.), palp {I. p.), paraglossa (pg.), lacinia (/. ). ' 



At the left upper corner is a cross section of the thorax of an insect, 

 showing the dorsal tergum, the ventral sternum (st.), the heart (/it.), the 

 gut {i.), the stigmata (s.), and tracheae (t.), the ventral nerve-cord («.), 

 the wings (w), the legs with coxa (co.), femur {/e.), tibia {ti.), tarsal 

 joints (ta.). 



