LEPID OP TER A. 
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 
mere 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 maxillae. 
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¬ 
ing, and armed at the end with a little claw. The abdominal 
legs, which are shed with the last larval skin, are thick. 
14 
