LEI^/DOPTERA. 193 



tube, which when not in use is coiled on the lower side of 

 the head between two forward-projecting appendages. This 

 long sucking tube is composed of the two maxillae, greatly 

 elongated, and fastened together side by side. In Figure 232 

 there is represented a side view of the maxillae of a moth; 

 and in Figure 233 a cross-section of these organs. Each 



Fig. 233. — Cross-section of maxillas. 



maxilla is furnished with a groove, and the two maxillae are 

 so fastened together that the two grooves form a tube through 

 which the liquid food is sucked. As a rule the maxillae of 

 insects of this order are merely fitted for extracting the 

 nectar from flowers, but sometimes the tips of the maxillae 

 are armed with spines, as shown in Figure 232. This enables 

 the insect to lacerate the tissue of ripe fruits and thus set 

 free the juice, which is then sucked up. Many moths do not 

 eat in the adult state ; with these the maxillae are wanting. 

 The two forward projecting organs between which the 

 maxillae are coiled when present are the labial palpi. In 

 some moths the maxillary palpi are also developed. 



The larvae of Lepidoptera are known as caterpillars. 

 They vary greatly in form and appearance; but are usually 

 cylindrical, and provided with from eight to sixteen legs, — 

 six thoracic legs, and from two to ten abdominal legs. The 

 thoracic legs, which are finally developed into the legs of the 

 adult, have a hard external skeleton ; and are jointed, taper- 

 insf, and armed at the end with a little claw. The abdominal 

 legs, which are shed with the last larval skin, are thick, 



