October, '17] BUSCK: MARMARA ELOTELLA 489 



Busck of the National Museum, who identified them as Marmara 

 elotella Busck. 



Special acknowledgments are due Dr. H. T. Fernald, Dr. G. C. 

 Crampton, and Dr. W. S. Regan for their encouragement and assistance 

 throughout the progress of this paper. For the identification of this 

 species and helpful suggestions the writer is deeply indebted to Mr. 

 August Busck of the United States National Museum and to Rev. 

 J. J. DeGryse of Staunton, Virginia. 



History and Ecology 



The Tineina, to which this species belongs, constitutes a large and 

 important group of minute moths including many destructive miners. 

 These fall roughly into two distinct classes according to their manner 

 of feeding. 



1. Tissue feeders. Those which feed on the internal parenchyma 

 tissue of leaves early in life and later may become external feeders. 



2. Sap feeders. Those which mine just beneath the cuticle destroy- 

 ing only a few layers of cells and feeding on the plant sap thus liber- 

 ated. 



This sap-feeding habit has been found only in two families, the 

 Phyllocnistidse and the Gracilariidse. The Phyllocnistids are sap 

 feeders throughout their larval life and include the following genera: 

 Marmara, Camermaria, and Phyllocnistis, while the Gracilariids in their 

 early instars are true sap feeders but in later instars become tissue or 

 external feeders and include the genera Gracilaria, Ornix, Acrocercops, 

 and Phyllonorcyter. 



Many interesting articles have been written based on the specializa- 

 tion shown by these sap-feeding larvae and their significance in showing 

 evolutionary steps from the more generalized tissue-feeding type. 

 The sap feeders are considered a very highly specialized group and are 

 probably of comparatively recent origin in the Lepidoptera. 



Practically all miners confine their feeding to foliage, but a few larvae 

 of the genus Marmara, established by Clemens {Proc. Ent. Soc. Phila., 

 vol. 2, 1863-64, pp. 6-7) mine just under the epidermal layer of 

 bark. Clemens described Marmara salictella which "mines the bark 

 of yellow willow tree" and gave a brief account of its life stages. He 

 also described Marmara {Gracilaria) fulgidella {Proc. Acad. Nat. Sci. 

 Phila., 1860, p. 6) mining in twigs of white oak and chestnut. Cham- 

 bers described Marmara {Phyllocnistis) smilacisella {Cin. Quar. Jour. 

 Science, 2, p. 107) bred from leaves of smilax. This species was re- 

 described with biological notes added by Braun {Ent. News, vol. 20, 

 p. 432, 1909). Busck described a new species, Marmara guilandinella 

 {Proc. U. S. Nat. Mus., vol. 23, p. 245), raining leaves of Guilandia 



