38 THE BUTTERFLIi:S OF NEW EXGLAXD. 



it is either entirely naked or is clothed throughout or in part with scales ; 

 the portion most frequently left bare is a median stripe along the under 

 surface ; in no case, so far as I have seen, are the antennae clothed with 

 hairs. The club is a peculiarity of butterflies among Lepidoptera, whence 

 the term "Rhopalocera" often applied to them. It consists of a regular 

 thickening of the apical joints and varies greatly in extent and appearance ; 

 in many cases, the joints increase in thickness to so slight a degree and so 

 gradually that, although the thickness of the club may be double that of 

 the stalk, it is difficult to determine where one ends and the other begins \ 

 usually, however, it is not difficult to mark the limits, and the more so as 

 the joints lose in length what they gain in thickness, and so present a 

 second mode of determination. The club, like the stalk, is usually cylin- 

 drical, but is not infrequently depressed, sometimes to a considerable 

 degree, or is even compressed or triquetral. It varies greatly in length 

 but may be said to be usually of al)Out one-sixth the length of the whole 

 antenna. It ordinarily increases in size nearly to the tip and then decreases 

 again with much greater rapidity, the terminal joint occasionally bearing a 

 produced point at the tip ; in the Hesperidae a number of joints are em- 

 ployed to form a long and tapering tip, sometimes nearly as long as the 

 rest of the club ; but in most butterflies the tip is bluntly rounded. The 

 club is usually straight, but occasionally droops or is curved upward, or, 

 as in the Hesperidae where the tip is produced, the tapering apex is turned 

 at a strong angle outward and backward. In the scaled antennae one or 

 two apical joints are usually bare to a greater extent below than above, as 

 is a broad field on the under surface, — an expansion of the median stripe 

 of the stalk. Often one or two slender carinae are to be seen upon the 

 under surface and some little dimple-like depressions (87 :8) arranged in a 

 longitudinal row. The contour of the surface is rarely interrupted at the 

 jointings, but in the arcuate clubs one side presents a serrate appearance 

 from the projection of the apices. 



The appendages of the mouth are the lab rum, mandibles, maxillae, 

 and labial palpi. 



The labrum is only a slight rounded projection of the centre of the 

 lower border of the front, transversely corrugated, soldered to the front and 

 thus immovable ; it serves by its position to guard the upper portion of the 

 x)eculiar maxillae. 



The mandibles, too, though somewhat variously developed, are greatly 

 aborted, immovably soldered to the head, inconspicuous in size, triangular 

 in form, and serve only by their situation to support the sides of the max- 

 illae, Avhich their apices usually touch. 



The nidxlUae are undoubtedly the most ])eculiar, as they are the most 

 characteristic organ of the Lepidoptera. In butterflies they are always 

 enormously developed, as very long and slender closed tubes, hollowed on 



