THE MICROSCOPE AND ITS REVELATIONS. 



which prevails among the Lepidoptera or Butterfly tribe, and which, 

 being pre-eminently adapted for suction, is termed the hau stellate mouth. 

 In these Insects, the labrum and mandibles are reduced to three minute 

 triangular plates; whilst the maxillae are immensely elongated, and are 

 united together along the median line to form the haustellium or true 

 * proboscis/ which contains a tube formed by the junction of the two 

 grooves that are channelled out along their mutually applied surfaces, 

 and which serves to pump-up the juices of deep cup-shaped flowers, into 

 which the size of their wings prevents these insects from entering. The 

 length of this haustellium varies greatly: thus in such Lepidoptera as 

 take no food in their perfect state, it is a very insignificant organ; in 

 some of the white Hawk-moths, which hover over blossoms without 

 .alighting, it is nearly two inches length; and in most Butterflies and 

 Moths it is about as long as the body itself. This ' haustellium,' which, 

 when not in use, is coiled-up in a spiral beneath the mouth, is an extremely 

 beautiful Microscopic object, owing to the peculiar banded arrangement 

 it exhibits (Fig. 430), which is probably due to the disposition of its mus- 

 cles. In many instances, the two halves may be seen to be locked together 



FIG. 430. 



Haustellium (proboscis) of Vanessa. 



"by a set of hooked teeth, which are inserted into little depressions between 

 the teeth of the opposite side. Each half, moreover, may be ascertained 

 to contain a trachea or air- tube ( 634); and it is probable, from the 

 observations of Mr. Newport, that the sucking-up of the juices of a 

 flower through the proboscis (which is accomplished with great rapidity) 

 is effected by the agency of the respiratory apparatus. The proboscis of 

 many Butterflies is furnished, for some distance from its extremity, with 

 a double row of small projecting barrel-shaped bodies (shown in Fig. 

 430), which are surmised by Mr. Newport (whose opinion is confirmed 

 by the kindred inquiries of Dr. Hicks, 628) to be organs of taste. 

 Numerous other modifications of the structure of the mouth, existing in 

 the different tribes of Insects, are well worthy of the careful study of the 

 Microscopist; but as detailed descriptions of most of these will be found 

 in every Systematic Treatise on Entomology, the foregoing general ac- 

 count of the principal types must suffice. 



631. Parts of the Body. The conformation of the several divisions 

 of the alimentary canal presents such a multitude of diversities, not only 



