2 BULLETIN 351, U. S. DEPARTMENT OF AGRICULTURE. 



HISTORY. 



The terrapin scale, Eulecanium nigrofasciatum Pergande, is a 

 native species which came to the notice of economic entomologists 

 about 1870. Mr. Theodore Pergande, of the Bureau of Entomology, 

 observed it as early as 1872. It was then believed to be the Euro- 

 pean scale Lecanium persicae Fab., an insect of similar habits. The 

 publications prior to 1898, for the most part, refer to it under the 

 latter name. Miss Mary E. Murtfeldt was the first writer to treat 

 of this insect at any length. She observed it in 1893, at Kirkwood, 

 Mo., but did not completely work out its life history. Her observa- 

 tions are recorded in Bulletin 32 [old series] of the Division of Ento- 

 mology, United States Department of Agriculture (1893), under the 

 name Lecanium persicae Fab. 



Dr. L. O. Howard treated this species in the Yearbook of the 

 United States Department of Agriculture for 1894 under the name 

 Lecanium, persicae Modeer, and there figured it for the first time. 



Mr. Theodore Pergande became convinced that this lecanium was 

 distinct from L. persicae Fab., and described it in Bulletin 18 [new 

 series], Division of Entomology, United States Department of Agri- 

 culture (1898), as Lecanium nigrofasciatum, new species. 



Since about 1898 the terrapin scale has gradually assumed more 

 and more importance as an enemy of the peach, until now it is feared 

 by the peach growers of Maryland and Pennsylvania more than any 

 other species of scale insect. Most of the States east of the one 

 hundredth meridian have mentioned this pest in their entomological 

 publications during the last 10 years. At the present time it appears 

 to be most abundant in portions of Maryland and Pennsylvania. 



DISTRIBUTION. 



There are no indications that the terrapin scale occurs outside of 

 North America. It is at present, for the most part, confined to the 

 humid area of the Austral Region, but there is danger that it may 

 ultimately invade western peach orchards, especially those in the 

 Austral Zones. This species has been taken in New Mexico and is 

 doubtfully reported from southwestern Colorado, but, so far as known, 

 it does not now occur in the other Western States. It has a slight 

 foothold in Ontario Province, Canada, mostly upon maple. At the 

 present time considerably more than one-half of all the known infes- 

 tations are found in Pennsylvania and Maryland. (See fig. 1.) 



In general this scale has advanced into the region of its principal 

 food plants, having spread through the peach belt of the Eastern 

 United States, and progressed northward beyond this belt by attack- 

 ing ornamental trees, of which the maples and sycamores seem to be 

 its favorite hosts. It has also extended its range in the Southwest 



