REVISION OF MOTHS OF PRODOXINAE 31 



After entering an ovum, the larva restricts its feeding to the de- 

 veloping seeds. Normally only one locule of the fruit is inhabited 

 by a given larva, and a relatively small number of seeds are de- 

 stroyed (sometimes less than a dozen) . Consequently, it is possible 

 for a single pod, contaming well in excess of a hundred seeds, to pro- 

 vide nourishment for several Tegeticula larvae. Seldom does this 

 occur, however, because the behavior of the moth is such that rarely 

 are more than a dozen eggs deposited in a smgle pistil. Trelease 

 (1893) reports (for T. maculata) that six eggs — one on either side 

 of each primary septum — are the usual number deposited in a pistU 

 of Yucca whipplei. Most eggs do not develop with the result that 

 one seldom finds more than 4-6 mature larvae per pod. In examining 

 over 70 pods of Y.Jilifera from Mexico, the author usually encountered 

 one or two larvae per pod (sometimes none) and rarely over three. 

 Riley (1892a) mentions one exceptional case of discovering as many 

 as 21 larvae within a single yucca pod. 



The larva of T. yuccasella normally attains maturity in about 

 a month — a period which also corresponds with the usual time re- 

 quired for the seeds of most yuccas to mature. Prior to emerging 

 from the fruit pod, the larva excavates an exit burrow toward the 

 outer surface of the fruit. However, an opening to the outside is 

 not completed at this time, and the larva retreats back to the seeds 

 to continue feeding, thus leaving a thin partition to block the exit. 

 The author observed this activity in specimens of T. yuccasella, 

 which were collected from one of the baccate-fruited yuccas, F. 

 flifera. A similar behavior may be true for the other species of 

 Tegeticula. 



Before the pods begin to harden or dehisce (as is the case with 

 most capsulate yuccas), the mature larva emerges from its host, and, 

 if necessary, lowers itself to the ground by means of a silken thread 

 (Whitten, 1894a). T. yuccasella has been observed emerging from the 

 pod at various times of day (usually at night) during or immediately 

 following a period of rain. Rainfall may be the final stimulus induc- 

 ing the other species to leave the host as well, for then the ground 

 is softened and more easily penetrable. The larva then bm-rows into 

 the ground and forms a firm, ovoid cocoon (figs. 29-30), consistmg of 

 silk, heavily intermixed with soil particles. 



Tegeticula yuccasella overwinters in the larval stage and normally 

 does not pupate until the following sprmg, a few days before the 

 flowering of the yuccas. This general behavior is probably true 

 in most instances for the other species; however, the length of hi- 

 bernation (or aestivation) for the final larval instar can be quite 

 variable as has been observed for T. synthetica. Riley (1892a) 

 reports receiving infested fruit containing larvae of this species in 



