THE bag-worm: a puzzle to EARLY ENTOMOLOGISTS. 83 



The immejise number of eggs whicli it contains and their arrangement, 

 is shown in a section of its i)upa within its cocoon-case at e. It is never 

 seen unless the case is opened, for within its inclosure, its entire life 

 in its moth state is passed. Indeed, the case shelters it during nearly 

 all of its larval stage, throughout its pupation, its transformation to 

 the moth, its copulation with tlie male, its oviposition, and its death. 

 Those who may desire to acquaint themselves more fully with the 

 many interesting details tliat enter into the life-history of this species 

 are referred to the excellent paper upon it, by Professor liiley, con- 

 tained in his First Report on the Insects of Missouri. 



Difficulties attending the Classification of the Species. 



The singular api)earancc of tliis insect, so unlike most of the Lepi- 

 doptera, was the occasion of much perplexity in its classification for a 

 number of years after its discovery. As may be seen from its synonymy, 

 it was originally described as a SjjJmix, althoii^h possessing none 

 of the characteristic features of the SphingidcB. Previous to this, it 

 had been believed to be a species of Tinea. Later it was regarded as 

 belonging to the uEgcridm. An interesting paper upon the species, 

 assigning it to its true position among the BornbycidcB, was communi- 

 cated by Mr. J. F. Stephens to the Trans. Ent. Sac. Lond., i, 1836, p. 

 76, under the title of " On the Appai*ent Identity of Sphinx ephemerae- 

 formis of Haworth with Psyche plumifera of Ochsenheimer," of which 

 the following is the substance. 



It appears that the original specimen was found in Yorkshire by Mr. 

 Boton, and was placed in Mr. Drury's collection. At the sale of this 

 collection, it was purchased by Mr. Donovan, and at an auction sale of 

 some of Mr. Donovan's insects, in the catalogue of which it was an- 

 nounced as "an undescribed Cossus ligniperda," it came into Mr. 

 Stephens' possession. Mr. Stephens was able to see, upon a cursory in- 

 spection, notwithstanding its mutilated condition, that it was not a 

 Sphinx or even one of the Sphingidoe. He referred it to " the singular 

 group known by the name of Sacktriiger by the Germans, and con- 

 sidered by some writers as belonging to another order of insects — 

 Trichoptera Newman, Phrygania Scopoli, and Tenthrido by Roda; in 

 fact it appears to be a Psyche of Ochsenheimer [Psyche plumifera], 

 so far as can be ascertained by the remains of the unique specimen." 

 Reasons are given why it could not bo classed among the ^-Egeridce 

 where it had been placed in the first volume of Illustrations of British 

 Insects, 1834, "nor had it any alliance with Zeuzera, to which genus 

 it would appear Donovan had assigned it." It did not fully agree 

 with Psyche, and a new genus — Thyridopteryx, was constituted for it. 



The above genus had been published by Stephens prior to the above 

 paper, in vol. iv, of his Illustrations, page 387,printed in 1835. 



