216 FOREST ENTOMOLOGY. 



Synopsis of Arboreal Species. 1 



A. Pygidium with four, rarely loithfive, groups of circumgenital glands. 



(1) Short serial group of lateral dorsal pores absent. Puparium 



reddish-pink in the young, smoky-grey in the old examples. 

 On oak ....... Zonatus. 



B. Pygidium always with five groups of circumgenital glands. 



(2) Serial group of dorsal pores present. Puparium flat, convex 



grey with a darker central zone. Hitherto found on fruit- 

 trees ...... Ostreseformis. 



C. Pygidium with club-shaped glands. 



(3) Groups of tubular spinnerets connected, with pores on both 



surfaces of pygidium ; circumgenital glands almost continuous. 

 Puparium bright-fulvous. On holly . . Britannicus. 



Aspidiotus zonatus (Frauenfeld). 



This insect is found on oak, but, so far, it has been rarely recorded. 

 One of the first discoveries was by myself at Agden, in Cheshire, Sept. 

 1892. It has been found fairly often in Cheshire, but never occurs 

 in any great numbers. 



As regards life-history, the egg-laying takes place early in May, and 

 the larvae hatch soon afterwards. As soon as the first larval moult 

 takes place, the sexes not only assert themselves, but they separate, 

 the males moving on to the leaves, and fixing themselves to the 

 midrib and veins, and the females congregating on the stem. But 

 though separated, it is, after all, only in the metamorphic stages, 

 inasmuch as it is only for the requirement of pupal development on 

 the part of the male. As the males emerge from the puparia on the 

 leaves with fully developed wings, it is obvious they have no distance, 

 or difficulty, to move from the leaf to the stem for nuptial rites and 

 associations. 



Aspidiotus britannicus (Newstead). 



This is a species which, so far, has only been found on holly and a 

 species of fern cultivated under glass in the immediate neighbourhood 

 of London. The scales are circular, of a dusky-brown colour, and on 

 the slightest disturbance fall readily from the leaf. The males can 

 be distinguished from the females by the smaller size of the scale. 

 1 Modified from Newstead's Monograph, vol. i. 



