48 NEW YORK STATE MUSEUM 



1 c II c s t i i,mi a Abb. & Sm., or a scale insect like the elm bark louse, 

 Gossyparia spuria .Mod., the pest would experience difficulty in 

 fintlinj;' other trees to its liking. An alternation such as sugar and soft 

 maples is very desirable because while the former finds a serious enemy in 

 the forest tent caterpillar, Malacosoma disstria Iliibn., the latt(,T is 

 comparatively e.\empt from its attacks, and wandering caterpillars would 

 therefore not find an abundance of food near at hand, as would be the case 

 where an entire row was composed of hard maples. Majjles and elms alter- 

 nated would prove of service in checking the rapiil distribution of such a 

 species as the elm leaf beetle, (". a 1 e r u c e 1 1 a luteola Miiil., and 

 would be an advantge even in the case of an outbreak of the spiny elm cater- 

 pillar, I^uvanessa antiopa Linn. A number of other instances could 

 be mentioned. Care should be taken in setting trees not onl\' to have 

 species side by side which are rarely affected by the same insect enemies, 

 but also varieties which will grow harmoniously and afford a pleasing 

 combination. 



The following table of some of the principal insect enemies of our shade 

 trees should prove of considerable service in avoiding undesirabh; combina- 

 tion from the standpoint of the economic entomologist. 



