LEPIDOPTERA. 193 



has only one. Attached to the second pair of maxillae 

 is a little horny tube, the spinneret {spn), by means of 

 which the caterpillar spins the web on which it walks. 

 Following the mouth parts are three pairs of appen- 

 dages in the form of true, jointed legs (PL IX., Fig. 

 143, /'-/'"), the first pair, like the first ring, being 

 the smallest. Each of these legs is terminated by a 

 homy claw. The second ring also bears a pair of 

 thread-like organs on its upper side. Two rings with- 

 out appendages succeed the leg-bearing segments. 

 Following these are four rings with four pairs of ap- 

 pendages in the form of fleshy, unjointed false legs, or 

 prop-legs, also called pro-legs {Is^-ls^), which serve 

 to prop up the long body, and are capable of exten- 

 sion and retraction. Of the four remaining segments, 

 only the last, or thirteenth, bears a pair of prop-legs 

 (//). All these stumpy prop-legs are provided with 

 tiny hooks which help the animal in clinging to an 

 object when one attempts to lift it. From the upper 

 side of the eleventh ring a pair of thread-like organs 

 is given off, similar to the pair from the second ring 

 behind the head. 



The caterpillar feeds voraciously so that it may store 

 up sufficient food for use during the changes that take 

 place in its quiescent or pupal stage. When ready to 

 become a pupa or chrysalis (the pupae of butterflies 

 are usually called chrysalids, because those of many 

 species are marked with brilliant golden spots), it spins 

 a mass of silk, fastening it to some object, and then 

 attaches itself to the silk by means of the last pair 

 of hooked prop-legs (see PI. IX., Fig. 145) and the 

 spines of the anal plate. While hanging in this posi- 



