6 PROCEEDINGS ENTOMOLOGICAL SOCIETY 



ON ACROCERCOPS STRIGIFINITELLA CLEMENS. 



BY CARL HEINRICH, Branch of Forest Insects, U. S. Bureau of Entomology. 



AND 

 REV. J. J. DEGRYSE. 



HISTORICAL. 



This interesting microlepidopteron was first described by 

 Clemens in 1860 under the name Gracilaria strigifinitella and 

 again by Chambers in 1872 as G. duodecemliniella. In 1875 

 Chambers redescribed it as Ornix quercifolieUa, appending the 

 following note: "a single specimen received from Miss Murt- 

 feldt who informs me that the larva curls down the edge of oak 

 leaves (sic!). In its earlier stages it is probably a leaf miner." 

 Busck in 1902 established the above synonomy and referred the 

 species to Walsingham's genus, Dialectica with the further infor- 

 mation that he had reared a single specimen from oak leaves 

 collected at Washington, D. C. Meyrick has since proved Dia- 

 lectica to be a synonym of Acrocercops and has placed strigi- 

 finitella in Group C (Gen. Ins. Fasc. 123) of that genuy with 

 another North American species, a single European and several 

 Australian forms. 



In the spring of 1913 one of the authors (Heinrich) found at 

 Falls Church, Va., a lepidopterous larva mining the midribs of 

 chestnut, chinquapin and oak leaves. Adults reared from these 

 and from similar larva in leaves of Fagus americana, 1 were de- 

 termined by Mr. Busck as Acrocercops strigifinitella. Furtm-i 

 investigations were continued by the authors during the past 

 summer. Chestnut appears to be the favorite food plant and 

 during mid-summer the work of the species is very common, 

 few of the young leaves escaping infestation, some bearing as 

 many as four separate mines. When the proper food supply i> 

 abundant, however, there is rarely more than one or two to the 

 leaf. There are a number of generations with considerable over- 

 lapping so that larvae are to be found any time from May till 

 well on into October. The first larval brood appears in spring 

 as soon as the leaves are formed. During July and August the 

 dominant period in the seasonal life of the species is reached. 

 Towards fall there is a gradual diminution in numbers, and during 

 October a partial dying out of the species, due in great measure 

 to the scarcity of new leaves which are necessary to the success- 

 ful maturing of the larva 1 . In the neighborhood of Washington, 

 D. C., the last larval brood appears early in October. The man- 

 ner in which the species overwinters has not been definitely 



1 Elkmont Term., T. E. Snyder, U. S. Bur. of Ent., Collector. 



