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NEW YORK STATE MUSEUM 



ELM BARK LOUSE 



Gossyparia ulmi Geof. 

 Elms along the Hudson river are unfortunate in suffering from a bark 

 louse, which, like the elm leaf beetle, is an imported insect and prefers 

 European elms. 



Characteristics. The affected trees are easily recognized in mid- 

 summer by their blackened appearance, which is caused by the growth 

 of a fungus in the honey dew excreted by the bark louse and covering 

 the foliage, limbs and ground beneath. In sunlight, minute drops of the 

 secretion may be seen falling in showers from the clusters of insects, 

 giving an idea of the drain this species must be upon the vitality of an 

 elm. The limbs which have harbored this bark louse for a few years 

 begin to die, the tree itself shows signs of weakness, and when it is at- 

 tacked by both the elm leaf beetle and this bark louse, succumbs shortly. 



The adult females are rather conspicuous and may be found on the 

 under side of the smaller branches, frequently clustered in masses and 

 appearing not unlike certain lichens (pi. 2, fig. 3). In June each is 

 about inch long, oval in outline, with the extremities slightly pointed, 

 and if crushed causes a reddish stain from the contained ova. The body 

 is surrounded by a mass of white, woolly secretion and the segmenta- 

 tion is also indicated by the same substance. The minute yellow young 

 make their appearance early in July and soon settle for a time on the 

 greener twigs and along the principal veins of the leaves. In the autumn 

 the back of the partly grown bark louse is covered with spiny processes' 

 secreting a white waxy matter. At this time most of the insects forsake 

 the leaves and settle for the winter in crevices of the bark. In the early 

 spring activity is resumed and the round of life completed. 



Remedies. As this insect is one of the sucking forms, securing its 

 nourishment through slender hair like mouth parts from the under-lying 

 tissues of the bark, its food can not be poisoned and recourse must be 

 had to contact insecticides, as will be explained later. 



TENT CATERPILLARS 



Clisiocampa dis stria Hiibn.: Clisiocampa americana Fabr. 



Complaints are received each spring of injuries to maples and other 

 shade trees by caterpillars. Examples submitted show that the offender 

 is more frequently the forest tent caterpillar, though occasionally its 

 near relative, the apple tree tent caterpillar, may be a partner in the mis- 

 chief. 



