10 tup: butterflies of new exgland. 



greater or less extent by papillae or tubercles bearing short or long hairs, 

 or else hairs are found arising directly from the surface ; for hairs in some 

 form, either sessile or seated on papillae, are always found upon some part 

 of tlie head ; even of the Lycaenidae, where this region is retractile within 

 the first thoracic segment (78-80) . 



I have licre described the head as it appears, not in its morphological 

 relations. There can be no question that ideally the head is composed of 

 several segments, most of which bear a single pair of inferior organs homo- 

 logous to legs, such as the jaws, maxillae, etc. So, too, I have spoken of 

 an outer and an inner maxillary palpus, and in treating of the imago shall 

 refer to a single pair as the maxillae ; but much confusion has arisen among 

 entomologists in the application of those terms ; ideally, and sometimes 

 actually, the maxillae of insects bear tln-ee palpi, any one of which may 

 become specially developed and receive tlie name of maxilla, while tlie 

 others are termed palpi ; thus the organ called maxilla in one group is not 

 alv\^ays strictly homologous to what bears that name in another group. 

 These, hoAvever, are not subjects for discussion here, and are only mentioned 

 to prevent misapprehension. 



The body and its appendages. The body is composed, as has been 

 stated, of thirteen segments (Compare Packard, Am. nat.,xix: 308). 

 The integument is only occasionally, and in special areas, of a corneous 

 nature, being usually more or less leathery ; the intimate structure is ex- 

 ceedingly variable, as shown by Minot (Arch. mikr. anat. 1886), and would 

 doubtless furnish excellent points of distinction and affinity if carefully 

 studied. The rings of the body resemble each other essentially, although 

 they may bear very different organs or vary considerably in size ; the first 

 and the last, however, often differ from the others in their general appear- 

 ance more than the rest do among themselves. The first is attached to the 

 head by a continuation of its more or less coriaceous integument, and varies 

 more than any of the others in size ; sometimes, as in Lycaeninae, it is very 

 tumid and permits the head to be entirely withdrawn within its folds ; or 

 the segment partially covers the head, as in the Papilioninae, and bears a 

 pair of extensible scent organs ; at other times it is extremely small, form- 

 ing as in the llesperidae, a sort of neck between the head and the rest of 

 the body ; and then the upper surface is usually covered in part by a horny 

 shield. The armature borne by the first segment generally differs from 

 that upon the other segments, being more diminuti\'e in size or less con- 

 spicuous in nature. Sometimes, however, as in some Argynnidi, a part of 

 it is more conspicuous. The terminal segment differs from the others more 

 by reason of its position than from any other cause : freciuently it is simply 

 rounded behind; at other times it develops, as in Chlorippe and the Saty- 

 rinae, a pair of backward projecting tapering prolongations ; very often it 

 has a slight central tuberculated extension. Usually the hairs are longer 



