The Moths and Butterflies 



359 



posed of the two greatly elongate maxillae, so apposed that a groove on the 

 inner face of one fits against a similar groove on the inner face of the other, 

 the two thus forming a perfect tube (Fig. 510). This sucking proboscis, when 

 extended, may protrude five or six 

 inches, as in some of the sphinx- 

 moths, or only a fraction of an inch, 

 as in the small moth "millers," but 

 when not in use it is so compactly 

 coiled up, watchspring-like, under 

 the head, and so concealed by a 

 pair of hairy little tippets (the labial 

 palpi) which project up on each 

 side of it that it is nearly invisible. 

 Of the other mouth -parts, the 

 upper lip (labrum) and under lip 

 (labium) are greatly reduced and 

 are not movable and flap-like as in 

 most insects, while the mandibles 

 are either wholly wanting or, as in 

 the sphinx-moths and some others, 

 represented only by small immov- 

 able functionless rudiments. The 

 palpi of the maxillae are also either 

 wholly wanting or present as mere 

 rudiments. The foregoing descrip- 

 tion of the mouth-part conditions 

 is true for the great majority of 

 Lepidoptera, but among the lowest 

 (oldest or most generalized) moths 

 some interesting examples of much 

 less specialized conditions occur. 

 Indeed in one family of minute 

 moths, the Eriocephalida, all the FlG " 57--A trio of apple tent -caterpillars, 



usual parts of a typical 



larvas of the moth Clisiocampa americana. 

 These caterpillars make the large unsightly 

 webs or tents in apple-trees, a colony of 

 the caterpillars living in each tent. (Photo- 

 graph from life by Slingerland; natural size.) 



a typical insect 



mouth are present and in a condi- 

 tion fitted for biting and chewing 

 and in all ways wholly comparable 

 with the condition in such biting insects as the locusts and beetles; the 

 mandibles are movable and truly jaw-like, the maxillae short and also 

 jaw-like and provided with several-segmented palpi, while both labrum 

 and labium are truly lip- or flap-like and fully movable, the labium 

 bearing 3-segmented palpi. Between this most generalized condition 



