EXTERNAL STRUCTURE OF THE BUTTERFLY LARVA. 21 



little globule in the mouth of the trumpet, and sometimes kept in its 

 place by a few microscopic bristles which surround its rim." 



These glandular setae are really the hairs of the primary tubercles. 

 Scudder, speaking of the change occurring in butterfly larvae (Butts, of 

 New England, ii., p. 805), at the various skin-moultings, says : The 

 mature Satyrine larvae have a rough skin the result of a multitude of 

 minute tubercles, each bearing a simple hair scarcely visible to the 

 naked eye ; in the young larvae of the Satyrids, the skin, instead of 

 being supplied with an almost innumerable number of microscopic 

 hairs, is furnished, in some instances, with an exceedingly scanty 

 number of little club-shaped bristles, proportionally many times longer 

 than the hairs of the adult .... arranged in definite longitudinal 

 series; in others, with compressed, ribbon-like hairs as long as the body, 

 serrated on one edge and bent in the middle ; on the abdominal 

 segments, these hairs point backward, and on the thoracic, forward. 

 In the Nymphalids, the segments of the young larvae are equal in size, 

 and have regular series of stellate warts ; in the mature larva, the body 

 is grotesquely hunched, while the warts have changed to very variable 

 tubercles, etc. In Anosia archippus the fullgrown larva is naked, but 

 adorned with a pair of long thread-like fleshy flexible tentacles at 

 either extremity of the body ; in the young larva, these tentacles or 

 filaments are absent, but their future position is marked by little conical 

 black points, while the body is covered with minute black bristles, 

 arising from still more minute warts, and arranged six on the back 

 of each segment (? i, ii, iii), and three on either side of the body 

 (? iv, v and vii). In the Vanessids, the larval spines are com- 

 pound in the adult, and arranged in certain definite rows ; in their 

 earliest life, these same larvae are furnished with long tapering hairs, 

 also arranged in definite series, but not occupying the same positions as 

 the spines of the mature larva. In Agraulis vanillae and Apostrophia 

 charithonia, two Heliconians, the appearance of the larva after the 1st 

 moult is entirely different from that preceding it. In the 1st stage, 

 the head is unarmed, and the body supports longitudinal rows of very 

 large papillae, each bearing a long slender naked hair with a delicate 

 ovate apical club. After the 1st moult, the head is armed above with 

 a pair of stout spines nearly as long as itself, bristling with distant 

 thorns ; and, in the place of the primary hairs, are long tapering spines 

 as high as the body, with a very slight basal enlargement, and 

 furnished along their whole length with minute papillae supporting little 

 needles, the position of these spines is quite different from that of the 

 papillae of the 1st stage, and, as if to mark this more distinctly, there 

 are but three longitudinal series above the prolegs ; these differences 

 become intensified in every subsequent ecdysis. The adult Euralid 

 (Lycaenid) larvae appear to be quite smooth, although covered with 

 microscopic hairs, whilst the newly-hatched larvae of this group are 

 provided with long spiculate primary hairs that sweep backwards 

 behind their bodies. In the Urbicolids, the primary setae of the newly- 

 hatched larvae are always shaped like little clubbed mushrooms. The 

 adult Papilionid larva is always nearly naked ; a few scattered hairs 

 may be found with a lens, with a few minute tubercles or smooth and 

 shining lenticles ; in some, the front part of the body is swollen, and 

 furnished with striking eye-spots ; at birth, however, the body is 

 always cylindrical and supplied with several prominent series of bristle- 



