320 



FOREST ENTOMOLOGY. 



characters in either surface. This is very well illustrated in fig. 300, 

 taken from Newstead's Monograph, which gives a general representa- 

 tion of the pygidium. It would be well to make a detailed study of 

 this figure, together with mounted specimens of the same. It is only 

 by a careful study of the various organs attached to this portion of 

 the abdomen that the specific characters of the sub-family Diaqnnce 

 can be definitely fixed. 



The genus Aspklioitis is generally considered the typical form of 



d d 



r'^ A c 

 e 



Fig. 500.— Pygidium, or anal segment, o/Mytilaspis pomorum, slwinng dorsal and ventral parts. 



a, anal opening ; b, dorsal tubular spinnerets ; c, marginal tubular spinnerets with their more 

 or less projecting pores ; d, median, second, and third pairs of lobes ; e, plates ; /, spines ; 

 g, vaginal opening; h, anterior, anterior lateral, and posterior lateral grouped circura- 

 genital glands. (From Newstead's ' Monograph of the British Coccidse.' Ray Society.) 



Diaspid scale, but as the genus CMonaspis is more frequently met 

 with in this country, it may be permissible to adopt it, from an 

 arboreal point of view, as the typical scale, giving a full account 

 of its life-history and structure. 



Genus Chioxaspis. 



So far as arboreal insects are concerned, there is only one species 

 in the genus — viz., C salins. The female puparium is elongate and 



