1»03 ENTOMOLOCxICAL SOCIETY. 51 



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proposed ahade trees is a matter of some little importance ; not so much perhaps, in the mat- 

 ter of actual food for the ordinary honeybee as in that of the increase of bees on account of 

 their great value as cross fertilizers of orchard trees and forage crops. From this point of 

 view there are five very important honey producers among the principal shade trees. These 

 are, in order of importance : American linden, tulip tree, black locust, horse-chestnut, and 

 sugar maple." 



When insects occur in destructive numbers in our forests it is an exceedingly difficult 

 matter to bring to bear any remedial treatment, in fact in most instances it is impossible to 

 cope with these enemies. In cases, however, where basswood trees are grown, or allowed to 

 stand, for ornameiital purijoses, it is usua'ly possible, when such are attacked by insects, to 

 apply a remedy. As it has often been stated in these pages, insects from a practical 

 point of view may, roughly speaking, be divided into two classes, viz. those kinds which 

 bite their food, such as caterpillars, and those which derive their sustenance by 

 sucking up their food in a licjuid form, by means of their beaks, as plant lice. For 

 the first class some poison, such as Paris green, must be applied to the foliage, which 

 will be eaten with the same, but for the second class some liquid, like kerosene emulsion, or 

 whale-oil soap, which will kill by contact, must be used. There are, however, many insects 

 which bore into the wood of the tree, and which cannot be reached by any of the above 

 remedies. Usually, however, it is only trees which have been injured in some way, as by 

 lightning, or wind, or are in an unhealthy condition, that are resorted toby the mature females 

 of these b iring insects for egg laying. For these, remedies of a preventive nature are usually 

 adopted, one of the best of which is to wash the trees, particularly the trunks with some 

 deterrent or malodorous mixture which has the effect of preventing the females from laying 

 their eggs. 



Insects, therefore, which teed upon the basswood may be divided as follows, viz : — 



Those which attack the foliage, • 



Those which occur on the bark, 



Those which bore into the Avood. 

 The following list of species covers all we have noted at Ottawa, as well as many which 

 have been recorded by other writers in the various, somewhat limited, public itions at our 

 disposal. 



ATTACKING THE FOLIAGE. 

 Order Homoptera. 



1. The Linden Tree-louse, Lachnus lo)igistigma, Monell. This is a species of plant louse 

 which feeds on the leaves, by means of its beak, through which it sucks up the juices. It is 

 found in Canada in late summer but does not occur anywhere in injurious numbers. 



2. The Obtuse Clastoptera, Clastoptera obtusa, Say. This is one of the tree hoppers, and is 

 recorded by Lintner in his report for 1891, as having been found on linden. The insect occurs 

 at Ottawa, but has never appeared in Ontario, Dr. Fletcher tells me, in injurious numbers. 

 Van Duzee recorded it as common on blueberry in the Muskoka Lakes District. 



Order Hemiptera. 



3. The Basswood Aphis, Pterocallis tilitv, L. has been very abundant at Ottawa the past 

 season. Early in July the plant lice were numerous in all stages, and specimens were kindly 

 identified by Mr. Theo. Pergande, through the courtesy of Dr. Howard. This plant louse is a 

 beautiful aphis, and like other aphids can be held in check by spraying with whale oil soap, or 

 kerosene emulsion. The trees attacked were covered with honey dew and blackened by the 

 fungus Fumago salicina which grows thereon. 



