SCALE INSECTS OF IMPORTANCE 295 



Recognition of scale insects. The majority of farmers and fruit- 

 growers experience great difficulty in distinguishing between the various 

 forms, and such will continue to be the case for some time to come ; but 

 it is hoped that the illustrations accompanying this account will enable 

 the non-scientific man to identify certain of these vexatious forms with 

 some approach to accuracy. It must ever be borne in mind_, however, 

 that, in attempting to identify an armored scale insect by external appear- 

 ances, we arenot studying the insect itself but a secretion subject to con- 

 siderable variation as a result of climatic and other external influences. 

 Scale insects occurring on trees near a railroad or in a smoky locality 

 may have their characteristic appearance much obscured by particles of 

 soot and dirt, and those living on trees infested to a considerable extent 

 with plant lice or other honeydew-excreting forms, may be more or less 

 covered with a sticky layer of dirt. These variations in appearance and 

 the minuteness of scale insects render their correct determination very 

 difficult for one who has not given the group special study. 



Key based on superficial characters of species treated. The 



above statement regarding the variability m the appearance of the scales of 

 these insects must be constantly borne in mind, and identifications made 

 in this manner, unless by an expert, should be regarded as provisional. 

 An effort should be made to secure both young and full-grown speci- 

 mens and, if possible, on different pieces of bark, some having few and 

 others having numerous individuals, as this will give a better idea of the 

 characteristics of the insect. A good magnifying glass or lens should be 

 used in examining the scales. A very serviceable one can be obtained 

 for from one to several dollars, and it is invaluable to the nurseryman 

 and fruit-grower in enabling . him to examine suspicious appearances 

 more closely. The characters given below do not apply to any of the 

 oval, usually somewhat hemispheric brown species of Lecanium, but 

 only to the species of armored scale insects treated of in detail. 



The species briefly characterized below are arranged in the order of 

 their present abundance in New York state ; and, if the description in the 

 first paragraph does not apply, pass to the second and so continue. It 

 may frequently happen that the specimen does not agree with the descrip- 

 tions given in any of the paragraphs, and in that case it is most probably 

 one of the species not treated, of which there are many; and the way to 

 ascertain the identity of such an insect is to send specimens to an ento- 

 mologist. 



I Adult female scales elongated, slender, pear-shaped, usually slightly 

 curved, almost ^ inch long and brown. Numerous white eggs may be 



