35 



family, the Micropterygoidea, have large mandibles which serve the 

 same purpose as in the Trichoptera. 



Superfamily MICROPTERYGOIDEA 



The most generalized lepidopterous pupae known belong to the 

 superfamily Micropterygoidea, which includes two families, the 

 Micropterygidae and the Eriocraniidae, characterized by the presence 

 of functional mandibles. Except for a description of the fragments 

 of the head by Chapman, no pupa of the Micropterygidae has been 

 described, but this family is undoubtedly the most generalized, because 

 the adults possess functional mandibles. 



The first complete life history of any American species of Erio- 

 craniidae was worked out by Busck and Boeving and published in the 

 Proceedings of the Entomological Society of Washington in 1914 

 (Vol. XVI, pp. 1 51-163). These authors gave a short description of 

 the pupa and included some excellent figures. A more detailed de- 

 scription is given here as this species furnishes a working basis for 

 the study of all other lepidopterous pupae. This was made possible 

 by the generosity of Dr. L. O. Howard, Honorary Curator of Insects, 

 U. S. National Museum, who donated some excellent material of 

 Mnemonica auricyanea collected this year by Mr. August Busck at 

 Falls Church, Va. 



The pupae of this species (Figs. 1, 2, 3) are very small, averaging 

 3 mm. in length in the males and 4 mm. in the females. The body is 

 covered by a thin transparent cuticle, which shows all the imaginal 

 parts in mature pupae, making it exceedingly difficult to distinguish 

 pupal structures from similar structures in the adult. It is also very 

 difficult to determine the number and position of the setae. 



The head shows all the sutures usually present in generalized in- 

 sects. The vertex is short, the epicranial suture fairly distinct and 

 extending to the lateral margins of the head. The fronto-clypeal 

 suture extends transversely, between the caudo-lateral angles of the an- 

 tennae. The front bears two long straight setae on each side of the 

 meson about half-way between the antennae and the cephalic margin 

 of the head. In the middle of the cephalic aspect, between the an- 

 tennae, arises a long, fleshy, beak-like projection which contains the 

 long tuft of hairs present in the adult. Just caudad of the front is 

 the clypeus and laterad of these are the genae in the usual position 

 for the Lepidoptera. The suture between the clypeus and labrum is 

 broad and somewhat chitinized, and closely appressed to its ental sur- 

 face is the tentorium, to which the mandibles are attached. The 



