116 LECANIUM HEMISPH^EIOUM. 



the dermis is thickly set with minute yellow specks or 

 dots. Form short ovate or subcircular, slightly 

 narrowed in front, and comparatively flat. During 

 the period of parturition the H -shaped carinaB almost 

 entirely disappear, only a very slight trace of the 

 lateral ones being visible in the old adults, as previously 

 described. 



So far only typical forms of the old adult female 

 have been described, being those which are found upon 

 the flat surface of a leaf or a comparatively large 

 branch of the food-plant. When, as is often the case, 

 the female takes up a position on a slender stem, such 

 as the hair-like stalk of the Adiantum, or other limited 

 areas such as a midrib of a leaf, the form becomes 

 much changed (figs. 1 c 9 1 d), and frequently much 

 dwarfed. This adaptation of form to environment no 

 doubt misled the earlier writers, and induced them to 

 create several species which, at most, can only rank as 

 phytophagous varieties, the anatomical details being 

 the same as in the typical L. hemisph&ricum. The 

 most marked varieties are given under the following 

 heads. 



a. Form slightly elongate-ovate and highly convex, 

 with the H -shaped carinae of the young female some- 

 times faintly traceable, more especially so at the sides. 

 Usually smaller than the type. This is the Lecanium 

 filicum of Boisduval, Signoret, and Douglas. 



(3. Form obtuse, oval, and highly convex. Colour 

 usually dark chocolate-brown, paler on the dorsum, 

 and suffused with blackish-brown at sides. This 

 answers in some respects to Lecanium hibernaculorum, 

 and is undoubtedly the form assigned to this variety 

 by Mr. Douglas,* and confirmed by Signoret. This 

 appears to be a well-nourished form ; I have found it 

 in this country on vigorous plants of Pteris sp. (fig. l/>) 

 and Stephanotis. 



y. Form resembling L. filicum in retaining the 



* I have examined examples of Mr. Douglas's co-types described in 

 'Ent. Mo. Mag.,' vol. xxiii, p. 78 (1886). 



