COCCIDJE. 205 



clearly pronounced that they afford valuable data, not only for the 

 distinction of sex, but for the separation of the various sub-families 

 and genera. These remarks are applicable to the "scales "of both 

 sexes, but more especially to the male scale or puparium. 

 Maskell l gives the following microscopical characters : 



(1) The presence of only one joint in the tarsus, or fourth joint of 



the leg, in males and females. 



(2) A single claw terminating the leg in males and females. 



(3) Two wings and two halteres in the males. 



(4) Two or more eyes or ocular tubercles, in addition to an ordinary 



pair of eyes. 

 With regard to the classification of scale-insects, it would be quite 

 superfluous under " forest entomology " to give all those sub-families 

 at present known in the British Isles, but the following genera, ac- 

 cording to Xewstead's Monograph, are arboreal in their habits : 



Synopsis of Sub-families. 2 

 Males with Simple Eyes. 



A. Abdomen of female terminating in a compound segment forming 



a definite pygidium. Anal orifice simple. 



(1) Insects with a separate covering scale (puparium) composed 



partly of moulted skins (exuviae) and partly of secretion. 

 Adult females without legs; antennae rudimentary ; men turn 

 monomerous ..... Diaspinae. 



B. Abdomen of female without definite pygidium. Anal orifice 



setiferous. 



(2) Females with a posterior extremity cleft ; anal orifice closed by 



a pair of dorsal plates. Larvae with prominent setiferous 

 lobes within the anal cleft . . . Lecaniinae. 



(3) Adult females with cleft extremity and anal plates, as in 



Lecanium. Larvae with abdominal lobes, as in Dacty- 

 lopiinae ..... Hemicoccinae. 



(4) Abdominal extremity not cleft, usually with a pair of more or 



less prominent setiferous lobes at margin. Abdominal ex- 

 tremity of larvae similar . . . Dactylopiinae. 



1 Scale-Insects of New Zealand. 2 From vol. i. p. 67. 



