4 RtiOPALOCERA AFRICA AUSTRALIS. 



the labruni or upper lip ; a lower pair of jaws, of a softer 

 nature than the mandibles, termed maxillce, which are fur- 

 nished with a small jointed organ springing from their 

 external edge called a maxillary palpus ; and a labium, or 

 under lip, also provided with a pair of palpi known as labial 

 .palpi. (At the tip of the lower lip is a conical, perforated, 

 cylindrical organ, which is the spinneret for the emission of 

 the silk secreted in two internal tubes.) With these effective 

 organs of mandu cation, these Larvae consume their food with 

 wonderful celerity. The three segments of the body next 

 the head each bear a pair of jointed, hard, cylindrical legs, 

 hooked at the tip, which answer to the six legs of the Imago. 

 It may readily be imagined that, in insects living on plants, 

 and having constantly to shift their position to obtain fresh 

 food, were the remaining nine segments entirely without legs, 

 it would be exceedingly difficult for the Larvae to support 

 so bulky and cumbersome a portion of their body, on the 

 slender twigs and leaves to which they are constantly clinging. 

 Accordingly, we find a greater or less number of these seg- 

 ments provided with supports in the shape of fleshy, wide 

 legs, which are more or less retractile, and fringed at their 

 extremity with numerous small hooked bristles. These are 

 known as false or pro-legs, and, in a Lepidopterous Larva 

 with its full complement, amount to five pairs, thus placed, 

 making the head the first segment : a pair on the seventh, 

 eighth, ninth, and tenth segments, and a pair on the thirteenth 

 or last segment. Some Larvae of Lepidoptera have only 

 four prolegs a pair on the tenth and a pair on the last 

 segment. It is very rarely that the hindmost pair are 

 wanting, and when this is the case the pair on the tenth 

 segment are always present, to support the hinder portion 

 of the body. Whatever may be the number of these 

 false legs (which are finally parted with on the assumption 

 of the Pupa state), they are not known to pass the limits 

 described above ; the fifth, sixth, eleventh, and twelfth 

 segments are never provided with legs. On the sides, above 

 the legs, are observable a row of minute punctures, often 

 circled with a bright, contrasting colour to that portion 

 of the skin immediately around them. These are the spi- 

 racles or breathing-pores, which are the mouths of air-tubes 

 connected with the two large trachea running along the 

 sides of the body. All Lepidopterous Larvae are provided 

 with silk, but only a portion of them spin cocoons previous 

 to entering on the Pupa state. Some of the latter mix earth, 

 fragments of wood, portions of leaves, &c., with the silk ; 

 while some, like the well-known silk-worm of commerce, 

 use silk alone in the construction of their pupa-cases. 



