DIURNAL LEPIDOPTERA. 79 



the first segment of the thorax, and that this very segment and tlii.s 

 only in passing from the low larval stage to the perfect form has be- 

 come greatly reduced in size, we must accept atrophy of these legs as 

 a conclusive mark of high organization. 



If again we examine the tongue, we shall find, as we pass upward, 

 a regular increase of complication in the structure of the papilla) or 

 organs of taste; at least this is true in the fifty or sixty species I have 

 examined. In the Swallow-tails and their allies, as in the skippers, 

 these papillae are merely minute distant tubercles, situated near the 

 tip, half a dozen or less on either side, seldom rising much above the 

 surface. In the gossamer-wiuged butterflies they are longer, much 

 more frequent and often mammilate at the tip. While in the brush- 

 footed butterflies they are crowded closely together, are often half the 

 breadth of the tongue in length and frequently trifid or tri-mammilate 

 at their tip. 



Finally, how do the modes of transformation affect the question ? 

 The moths, as a general rule, pass their chrysalis stage in a cocoon of 

 silk or earth, in which they lie loosely in a horizontal position. The 

 skippers also undergo their transformations in a cocoon, a light fragile 

 aff^air it is true, but still unquestionable a cocoon ; one or two other 

 butterflies also make a slight coco'in, wherein to change to chrysalis ; 

 and these few instances, such as Parnassius and Zegris, belong exclu- 

 sively to the same family as the Swallow-tails, though not to the same 

 precise division.* The skippers, however, do not lie loosely in their 

 cocoons, as do the pupae of moths, but spin at either end a Y-shaped 

 thread, into the centre of one of which they plunge their hooked 

 cremaster, while in the upper loop of the other they rest their body. 

 Now when we reach the next family, the typical butterflies, the cocoon, 

 save in the exceptional instances mentioned, is lost, while the silken 

 attachments of the chrysalis still remain, modified to suit the circum- 

 stances. Instead of the Y-shaped band, wherein to plunge the cre- 

 master, a carpet of silk is woven upon some branch, into the midst of 

 which the hooks are thrust, while the omission of the stem of the 

 other Y leaves a loop or girt about the middle. To accommodate the 

 chrysalis thus hung next a solid substance, instead of in the middle 

 of an oval cell, the segments of the abdomen must curve upward to- 



* Mr. W. II. Edwards (Trans. Am. Ent. Soc. VI. 3), endeavors to explain this 

 cocoon in Parnassius as a " biological necessity" from its exposed position on 

 Alpine heights; probably he was not aware of the occurrence of the cocoon in 

 Zegris, which is common on the plains of Southern Spain. See Rambur, Faun. 

 Ent. Andal. II, 247, pi. U, fig. 4. 



