31 PROCEEDINGS OP THE ACADEMY OF 



referred to. Why this deviation from "what is usual in the case of 

 the Brazilian species ? The conclusion is not far-fetched. There 

 seems to be a tendency towards the abandonment of a habit which 

 has been proverbial. What the circumstances are, which are de- 

 termining this change, it is not easy to divine. In this climate 

 cocoons serve to protect their inmates, when placed in exposed 

 situations, from undue moisture. Experience has shown that they 

 are capable of enduring with impunity a high degree of cold. 

 Successive alternations of temperature from cold to warm, and 

 vice versa, are accompanied by injurious effects. In tropical 

 countries where the year is divided into two seasons, the wet and 

 the dry, it is during the latter that the larva changes and pre- 

 pares for a winged existence; consequently, the necessity for 

 cocoon-making does not exist. 



The cocoon being of little service to this Brazilian larva, other 

 than as a suitable and comfortable support, being a relic of the 

 past, will doubtless in time be abandoned. The insect will by de- 

 grees adapt itself both structurally and functionally to the new 

 conditions of its environment, and support itself by a girdle like 

 that of the Papilionidse. 



If butterflies have been evolved from moths, we should expect 

 to find some evidences of the fact, if not in the forms of existing 

 species, at least to a certain extent, in the gradations which can be 

 established between cocoon-manufacture and the almost complete 

 abandonment of the art, save in a rudimentary state, if the girdle- 

 like-support of the Papilionidse and others can be construed as 

 the traces thereof. If moths are the parents of butterflies, an ex- 

 amination into the past histoiy of our globe as contained in its 

 rock-structure, ought to afford some confirmatory evidence. We 

 should expect to meet with some traces of moths, as proofs that 

 they were the earliest lepidopterous life that inhabited this globe. 

 A review of palaeontological literature upon this subject dissi- 

 pates all suppositions to the contrary. 



In the iron-stone concretions from the Carboniferous beds of 

 Morris, Illinois, besides the remains of Neuroptera proper and 

 Pseudo-neuroptera, there have been discovered two other forms 

 of extinct articulate life. Naturalists have described one form as 

 a centipede, the other as a caterpillar of a moth; the caterpillar 

 was referred to the family of Arciians to which our woolly bears 

 belong. As to the propriety of so doing, Mr. Scudder, of Mass., 



