28 



ameter, being less than 3 mm ) is much too small for my specimens and 

 those described by Dr. Douglas. The latter author considers these 

 three froms as belonging to three distinct species. The specimens in 

 my own collections indicate that Mbernaculorum is undoubtedly distinct 

 from the other two forms, being larger, destitute of distinct lateral ca- 

 rinae, and the flattened margin is much narrower than in either of the 

 other forms. I incline to the belief, with Maskell, that hemisphcericum 

 and Jilicum are but forms of one species, but to settle this point defi- 

 nitely it would be necessary to compare the larvae of these various forms 

 which as yet I have not had the opportunity of doing. Neither of these 

 three forms are at all common in this portion of the State. 



The Black Scale. 

 (Lecanium olece Bern.) 



This scale-insect is widely distributed, being found in nearly every 

 portion of the civilized world, living in greenhouses in the colder coun- 

 tries and in the open air in the warmer climates. It is not so destruc- 

 tive to plants as some of the other species are, and I have never known 

 of a single instance where a tree or plant has been killed by them, al- 

 though they sometimes occur upon certain trees in immense numbers. 

 The injury caused by them is seen in a general weakening of the entire 

 tree, which, if badly infested, is rendered unsightly by reason of the 

 black fungus which exists upon the liquid exudations of these insects. 

 Citrus trees are very subject to the attacks of these scales, and the 

 fruit of trees infested by them is rendered so unattractive in appear- 

 ance on account of the black fungus above referred to that its market 

 value is much less than it otherwise would be. Among deciduous trees 

 the Olive and Apricot appear to be more subject to the attacks of these 

 scales than any of the other kinds. The Black Scale, however, does 

 not appear to be very particular as to the kind of plants upon which to 

 gain a sustenance, as will be seen by reference to the following list of 

 plants and trees upon which I have found full-grown specimens of this 

 scale-insect : 



Citrus trees. Lombardy Poplar. 



Apricot. Myosporum. 



Almond. Melaleuca purpurea. 



Sycamore. English Laurel. 



Rhus integrifolia. English Holly. 



Seteromeles arbutifolia. Beech. 



Oleander. Ash. 



Baccharis viminalis. Acer dasycarpum. 



Ficus macrophylla. Rhamnus crocea. 



Habrothamnus elegans. Pepper Tree. 



Guava. Grevillea robusta. 



Irish Juniper. Ligustrum japonicum. 



