12 U.S. NATIONAL MUSEUM BULLETIN 25 5 



These relationships will be discussed further in a future paper treating 

 the New World Incurvariinae. 



The principal reasons for recognizing two distinct groups within 

 the Incurvariidae are observed in the larvae. The Prodoxinae 

 characteristically possess larvae which lack prolegs and crochets; 

 thoracic legs are known only in the genus Tegeticula. In contrast, 

 at least some remnants of prolegs are beheved to exist in all Incur- 

 variinae, in addition to the presence of thoracic legs. The larvae of 

 a few species of Eui'opean Incurvariinae (e.g., Lampronia capitella) 

 are known to bore in plant shoots. Although these particular species 

 are internal feeders, as are all members of the Prodoxinae, their 

 larvae, nevertheless, possess a normal complement of prolegs, at least 

 in the later instars. 



At present, it is difficult to summarize the evolution of the Pro- 

 doxinae. I believe, however, that some attempt should be made, 

 largely because of the paucity of existing information on this subject, 

 and also as a means of explaining the arrangement of genera presented 

 herein. Considerably more work needs to be performed on the basic 

 morphology of the primitive Lepidoptera, as well as on their life 

 histories. Information from such studies, in connection with the 

 discovery of new species, may greatly modify some of the following 

 speculations. After a study of the Incurvariinae (now in progress) 

 has been completed, it should be possible to discuss more adequately 

 the relationships of the family. 



As mentioned previously, the Prodoxinae represents a New World 

 radiation of the Incurvariinae that evolved as borers in certain agavoid 

 plants, the genus Yucca in particular. I consider the Incurvariinae 

 to resemble most a possible ancestral group, primarily because of 

 their more archaic distribution (holarctic) and the more generalized 

 form of the larva. At present I regard the genus Lampronia as the 

 most primitive component of the Incurvariinae; structure of the head, 

 legs, and ^vings are the basis for this belief. In addition, certain 

 members of this genus most resemble the Prodoxinae in Ufe history as 

 well as morphology. For example, at least four species of Lampronia 

 are known to be internal borers; however, a majority of the known 

 species of Incurvariinae are leaf miners in the early instars and later 

 construct a lenticular case and commence to feed externally. 



The suggestion of an internally feeding ancestor for the Prodoxinae 

 is not to imply necessarily that this is the most primitive form of 

 larval behavior in the Incurvariidae, but merely that this habit was 

 an early specialization. Powell (1964) has stated that evolution 

 within the Lepidoptera has preceded from the wood boring habit 

 toward the external feeding habit as a means of adaptive radiation 

 within separate phylogenetic lines. To support this thesis, Powell 



