326 TRANS. ST. LOUIS ACAD. SCIENCE. 



In the home of the Yuccas, and more particularly in the home 

 of the caulescent species, like T". aloifolia and T. gloriosa^* 

 persons who have occasion to dig up the roots, or subterra- 

 nean trunks, often notice that these are bored and hollowed out 

 along the axis (Fig. 25, <5), the burrow cylindrical, and lined 

 at its upper end with silk, which is generally intermixed with 

 a white, glistening, soapy powder. These tunnelings are made 

 by our Yucca Borer, which dwells therein ; and their presence 

 may generally be detected by masses of excrement observable 

 among the leaves, and by certain chimney-like projections made 

 by the twisting and webbing together of the more tender heart- 

 leaves, or even of the flower-stalk, after they have been partly 

 devoured, into a sort of funnel, from which the excrement is 

 expelled (Fig, 25, a, a). The tunnelings weaken the trunk 

 and induce rot, so that the plant is not unfrequently prostrated 

 thereby ; and as the insect is sufficiently common in the Gulf 



[Fig. 26.] 



o 



Megathymus yucc^ : Female. 



without difficulty, being glutinous, and generally remaining in an entire lump on the con- 

 tracted and curled anthers, so that a single anther may furnish the required amount. After 

 stating (p. 60 of these Transactions) that my account of the mode of collecting the pollen 

 ■was founded on repeated observation, and showing that the spinous maxillary tentacles are 

 admirably adapted to the purpose, the opinion that the smooth tongue can alone be em- 

 ployed for the purpose is unworthy so careful a writer as Prof. Zelle"-; and as for the reflec- 

 tion in the last sentence which I have quoted, I am vain enough to believe that there is no 

 other provocation for it than a certain ill-will on my critic's part. It comes, too, with all 

 the less grace from one who confessedly made hasty and incorrect observations on the posi> 

 tion of the species. From one less honored and esteemed, such captious remarks would 

 have received no notice at my hand. 



* Though I have positive proof of its working in aloifolia, gloriosa, Andjilamentosa, 

 its range does not seem to be co-extensive with tliis last species, as I believe the insect has 

 not yet been reported north of latitude 36". 



