48 Riley Notes on Yucca Insects and Yucca Pollination. 



middle of the thorax ; characters not noticeable except in well- 

 preserved specimens. The white portion of the antennae extends 

 also in these two specimens beyond the basal third and fully to 

 one-half the length of the organ. The four collected specimens 

 from Professor Trelease indicate considerable variation ; in one 

 specimen the outer arm of the transverse Y-band across the pos- 

 terior portion of the wing being absent, while in another it is 

 broken, as is also the basal portion of the median band. The 

 same is true of the band across the middle of the wing, while 

 the upper portion of this band is connected with the basal band. 

 The larva shows no striking characteristics, but is very similar 

 to most other Prodoxid larva?, being uniformly yellowish-white, 

 the head and cervical shield anteriorly slightly darker, the ocelli 

 black, and the mandibles brown and three-toothed. 



Prodoxus reticulatus. One of the specimens received from Tre- 

 lease taken in flowers of Yucca whipplei, variety graminifolia, 

 at Arrowhead Springs, in California, would indicate that this 

 species, which I described from three females from Los Angeles 

 county, California, and the habits of which were not known, 

 breeds in some part of this Yucca. The single 'female sent by 

 Trelease is interesting in that it shows some variation in the 

 direction of coloradensis, especially by the separation of the basal 

 half of the W-shaped band. 



Prodoxus cinereus. A section of the flower-stem of Yucca 

 whipplei sent me by Mr. Coquillett last July contained a number 

 of different larva?, and among them most numerously one which 

 subsequently proved to be the larva of Prodoxus cinereus. We 

 have known that this species breeds in the main stem of this 

 Yucca, but none of the early states had been observed. The 

 larva is remarkable in that it differs materially from the typical 

 Prodoxus larva. It is, first of all, very much more elongate, 

 with the sutures between the segments more strongly impressed. 

 It is, further, more uniform in diameter than the typical Pro- 

 doxus larva; but the most striking feature is the anal segment, 

 which bears on its ventral plate two stout, brown, decurved 

 horns resembling those of the larva of Trogosita in Coleoptera, 

 except that these are curved in the opposite direction. I add 

 a technical description : 



PRODOXUS CINEREUS. Larva. Average length when full grown, 8.25 mm. ; 

 body elongate, but slightly curved, the joints moniliform ; head rather 

 large, more horizontal, and more free than in other species, light brown in 



