REVISION OF MOTHS OF PRODOXINAE 7 



a segment of the palpus. Thus, by following this line of reasoning, 

 the homology as proposed by Smith becomes less acceptable. Pri- 

 marily for convenience and because its homology is so uncertain, the 

 segment bearing the maxillary tentacle is considered in this paper to 

 be the first segment of the maxillary palpus. 



Superficially, the segment bearing the tentacle most resembles a 

 typical palpal segment, especially in the males of Tegeticula, Para- 

 tegeticula, and in all other members of the Prodoxinae. Riley, 

 Trelease, and later authors stated that the males of Tegeticula and the 

 females of Prodoxus possess a rudimentary tentacle on the basal 

 segment. Such a rudiment is present to a slight degree in both the 

 males and females of Prodoxus (fig. 51) ; however, the base of the second 

 palpal segment is more modified than the basal segment itself. 



Crampton (1923) later studied the maxilla of T. yuccasella but was 

 unable to homologize the tentacles, providing them with a new 

 name — the palpiprocess. As illustrated by Crampton, the maxillae 

 of Sialis (larva) and Machilis bore some resemblance to those of 

 female Tegeticula in possessing a palpifer which gave rise to a digitate 

 process, referred to by him as the galea. 



Examination of the most primitive Lepidoptera offers httle toward 

 an understanding of the general problem. A 5-segmented palpus is 

 present in the Micropterygidae which shows no evidence of basal 

 specialization. However, from the basal segment of the labial palpus 

 arises a digitate structure (fig. 53) which Tillyard (1923) has referred 

 to as a sensory process. It does not seem unreasonable to suppose 

 that a similar process could have developed from the comparable 

 segment of the Tegeticula maxilla. 



On initial examination it may appear that the maxillary tentacles 

 are derived from the lacinia. In the Micropterygidae this appendage 

 is present as a greatly reduced, bluntly pointed process, lying close and 

 shghtly based to the similarly reduced galea. Considering the struc- 

 tm-e and origin of the lacinia in nearly all insect orders, however, there 

 seems httle probabihty that this organ is in any way involved wdth 

 the maxiUary tentacles of Tegeticula. 



The primary function of the tentacles is to aid the female in gather- 

 ing yucca pollen; indeed, Avithout these appendages it is evident that 

 pollen can not be collected (see p. 59). In structure the tentacles are 

 tubular and membranous with numerous, short, hooked hairs scattered 

 over the inner surfaces. These hairs engage the pollen as it is gathered 

 and greatly assist in retaining it. Extension of the tentacle is probably 

 by means of fluid pressure with muscular action perhaps playmg a 

 major role in retraction. 



The labium will be mentioned briefly m this section only in regard 

 to sensory organs located at the apex of the terminal palpal segment. 



