HEMIPTERA. 14! 



oaks wherever they grow. These insects are remarkable for the 

 wonderful gall-like form of the adult females. So striking is this 

 resemblance, that they have been mistaken for galls by many ento- 

 mologists. Fig. 126 represents a species of this genus upon Quercus 

 agrifolia. The gall-like swellings on the stem are the adult females; 

 the smaller scales on the leaves are the immature males. 



Sub-Family II. LECANIN^E.* 



In the present state of our knowledge of this sub-family there is 

 nothing to add to the characterization of it given in the table on page 

 136. The most available character for recognizing these insects is 

 the presence of the subtriangular anal plates (Fig. 121). Usually, 

 the body is elliptical or circular in outline, with a deep incision at 

 the caudal end, .leading to the anal opening (Fig. 121). Although 

 as a rule these insects remain fixed to one spot after the wandering 

 larval stage, I have seen the adults of certain species move from one 

 place to another. It is a curious fact that in certain species, among 

 them the most common ones, as L. hesperidum, the males are un- 

 known. It seems probable that they rarely, if ever, occur. Only 

 three genera have been found in the United States. These are dis- 

 tinguished as follows : 



A. Body naked or nearly so. 



B. Female secreting a mass of cottony material in which the eggs are laid. 



Fig. 127. 2. PULVINARIA. 



B. Female laying her eggs beneath her body, not excreting a mass of cot- 

 tony material. i. LECANIUM. 

 AA. Body covered with a layer of wax. 3. CEROPLASTES. 



Lecdnium. The species of the genus Lecanium abound every- 

 where ; they occur on all kinds of plants both in conservatories and 

 in the open air. Some of them are known to gardeners as " Soft- 

 scales." The genus is one that is easily recognized, but no one has 

 yet found satisfactory characters for separating the closely allied 

 species. I have figured three of the more common forms. Plate 

 V. 2 is of Lecdnium hesperidum. This is a representative of a group 

 that includes our most common species. They are an elongated 

 oval in outline, nearly flat, and smooth and shining. 



Lecdnium hemispharicum (Plate V. 3) is a much more convex 

 species, as its name indicates. It is common in conservatories. 



*LecanInse, Lecanium : lecane (^eKarrf), a dish 

 IO 



