21 



caterpillars and the pupae. This causes a high mortality every season, 

 especially during a period of heavy rainfall ; probably for this reason 

 the autumn brood suffers more heavily than the earlier one. 



ViNAL (S. C). Notes on the Life- history of Marmara elotella, Busck, 

 a Lepidopterous Sap Feeder in Apple Twigs. — Jl. Econ. Entom., 

 Concord, N.U., x, no. 5, October 1917, pp. 488-496, 1 fig. 



Investigation into serpentine mines in the bark of apple twigs in 

 Massachusetts has proved them to be the work of sap-feeding Tineid 

 larvae of the genus Marmara. Adult moths, which have never 

 previously been reared from apple, were bred in the laboratory and 

 identified as Marmara elotella, Busck. Miners almost invariably con- 

 fine their feeding to foUage, but a few larvae of the genus Marmara 

 mine just under the epidermal layer of bark. Marmara salictella has 

 been observed mining the bark of the yellow ^vi]low tree ; M. {Gracilaria) 

 fulgidella mines in twigs of white oak and chestnut. Leaf-mining 

 species include M. {PJiyllocnistis) smilacisella, on smilax ; M. guilmidi- 

 nella, on Guilandia bonducella ; M. arbutiella., on arbutus trees ; and 

 31. opuntieUa, on Opmitia sp. An unidentified species of Marmara 

 mines in orange peel in Southern California. 



M. elotella is apparently ^^^dely distributed within the State, apple 

 twigs in many places sho^^^ng the long, narrow and tortuous mines 

 that characterise all species of Marmara. The larvae separate the 

 cuticle of the bark from the green bark by cutting through a row of 

 cells. From the beginning of each mine the tunnel gradually widens 

 as it nears completion, the average length being between 2 and 3 feet. 

 Similar mines due to different species are found on poplar, ash and 

 pine. 



The eggs of M. elotella are deposited singly on the smooth bark of 

 apple twigs, generally on the two-year-old wood, to which they are 

 attached by a mucilaginous secretion. After about ten days the young 

 larvae hatch, and, AAithout exposing themselves, immediately enter the 

 twig and begin to construct mines which extend partly around the 

 twig before running lengthwise. After moulting twice, they hibernate 

 in the mines, being protected from climatic changes by the dead bark 

 covering the tunnel. In the spring they are again active, moulting 

 again about mid-May and becoming mature during June ; they then 

 become quiescent on one side of the mine. Hitherto all species of 

 this genus have been described as emerging from their mines and 

 spinning cocoons, surrounded with frothy globules, in protected 

 crevices. M. elotella differs from these species in having a pseudo- 

 pupal stage during which it becomes more cylindrical in shape and 

 finally breaks away the epidermal covering of the tunnel. The spinning 

 larva then emerges and spins a few threads, forming with the cuticle 

 a longitudinal fold under which the white silken cocoon is spun. Upon 

 completion of the cocoon the larva transforms to the pupa, in late 

 June or early July. The moths emerge towards the end of July, the 

 species thus requiring a full year for its life-cycle. 



An unidentified Tlhalcid parasite is an efficient control of these 

 miners, many of its pupae being found within the cocoons of 

 M. elotella. 



