A Lepidopterous Insect. 123 



A LEPIDOPTEROUS INSECT 



(Sphinx sp.). 



* 



LARVAL STAGE. 



External Anatomy. The body of the lan>a or cater- 

 pillar is elongated and vermiform and, like that of Arthro- 

 pods already studied, is made up of serially arranged seg- 

 ments or metameres. 



The head bears, anteriorly and laterally, a pair of large, 

 convex parietal plates which meet above in the median line 

 and enclose, lower down, a smaller, median, triangular frontal 

 plate. The ocelli are found as a series of pigmented dots at 

 the lower anterior portion of each parietal plate. How 

 many ocelli are there ? 



The first pair of cephalic appendages, the antenna, take 

 their origin from the lower anterior angles of the parietal 

 plates. Each antenna is made up of several joints. 



The opening of the mouth will be found midway between 

 the antennae. It is bounded anteriorly by a two-lobed upper- 

 lip or labrum, and laterally by a pair of strong chitinous /#/.? 

 or mandibles. In what plane do the mandibles move ? 



The maxilla lie immediately posterior to the mandibles. 

 Each is provided with a small jointed organ, the palpus. In 

 the median line between the maxillae is the cone-shaped 

 lower-lip or labium. It bears the external opening of the 

 duct leading from the silk-glands. 



