REPORT OF THE STATE ENTOMOLOGIST I913 



23 



more disfiguration than damage, since there is generally only a 

 small portion of the foliage involved. 



Habits and life history. Early last June our attention was 

 called to the work of this insect (kindly determined by Mr W. D. 

 Kearfott) by Mr Henry Hicks, Westbury, N. Y., because of its 

 being so numerous that the browned, mined leaves rendered many 

 ornamental arbor vitae unsightly and therefore unsatisfactory. 

 Occasionally this insect may become so abundant as to afifect a 

 considerable proportion of the foliage and give infested trees a 

 rusty, brown appearance. The 

 operations of the pest are usually 

 confined to a terminal half inch of 

 leaves here and there, and sometimes 

 its work is so restricted as to involve 

 only one-half of a portion of the 

 leaflet. Transformation to the pupa 

 occurs in the mine, the moth emerg- 

 ing therefrom about the midde of 

 June, the dates in our rearings rang- 

 ing from the 9th to the 17th. There 

 seems to be an erroneous association 

 by Packard of this adult with a 

 cocoon and, with this in mind, there 

 may be a question as to his having 

 described the true larva of this 

 species. Kearfott ^ states of a closely 

 allied species, R e c u r v a r i a t h u - 

 j a e 1 1 a Kear., that the eggs are de- 

 posited in the summer, the young 



larvae begin mining the leaves of the preceding year and eventually 

 transform within the mines, the moths appearing in June. We found 

 nearly full-grown larvae next to the green portion of browned leaf- 

 lets October 14th and have reared this species from the leaves of 

 Juniperus utahensis, kindly forwarded by Prof. E. Bethel 

 of Denver, Col. This is probably a fairly correct outline of the life 

 history of the species under consideration. A. thuiella has also 

 been reared, we are informed by Mr Kearfott, by the late Professor 

 Slingerland. A parasite, Pentocnemus bucculatricis 

 How., kindly determined by Messrs Howard and Crawford, was 

 reared from leaves infested by this leaf miner. 



Fig. 5 Spray of arbor-vitae 

 showing tips injured by the leaf 

 miner (natural size, original) 



'1903, N. Y. Ent. Soc. Jour., 11:154-55. 



