coccid^:. 215 



considered as analogous to some species of Aphidae, in which males 

 have only heen found after an interval of several years, otherwise the 

 sex may have heen determined (as sexes of insects often are) by the 

 food-plant. With regard to finding it on certain food-plants, New- 

 stead remarks, " Here in England, however, I have met with it freely 

 on Cytisus and Vacci?iium, and sparingly on heath." 



Its habits are much the same as the Chionaspis on ash, &c. 

 At the end of August or early in September the female lays her eggs, 

 which remain under the scale during the winter. They are white, 

 and hatch out in Cheshire about the end of May, but not until the 

 middle of June (June 16, 1900) in Northumberland. The males, 

 when found, have appeared in July. 



Xewstead gives the following detailed description of the pygidium 

 viz. : " Pygidium (fig. 202) with five groups of circumgenital glands, 

 subject to great variation in number. Dorsal tubular spinnerets, 

 small and cylindrical, are arranged in three series, the first, opposite 

 the lateral ventral glands, form a long scattered band terminating near 

 the anus ; intermediate series in a single row forming an incomplete 

 arch, with an outward lateral series extending from the middle almost 

 to the margin ; third series following the articulation of the pygidium 

 with the segment. On each side of median lobes along the margin 

 are six tubular spinnerets, of which the second and third, and 

 fourth and fifth, are arranged in pairs. Anus a little in front of the 

 anterior group of ventral glands. Vaginal opening almost central. 

 Median lobes almost as broad again as long ; lateral margins usually 

 straight ; posterior margin centrally lobate, with one or two notches 

 on either side. Second and third pair of lobes small, almost touching, 

 have their margins rounded and entire or bluntly and irregularly 

 dentate. Plates long and spine-like, usually one median and four 

 lateral pairs." l 



Genus Aspidiotus. 



Female puparium more or less circular, and either raised or com- 

 paratively flat in centre. Exuviae central or conspicuously to one 

 side of centre. Secretionary covering often very thin. Females show 

 great variation in the character of the pygidium. Hence, from a 

 microscopical or specific point of view, it is advisable to study every 

 available species on different host-plants. 



Male puparium circular, but much smaller than the female scale. 



1 Newstead, vol. i. p. 196. 



