THE MALE. 11 



species of Pseudococcus infesting laburnums, which 

 generally hatch towards the end of March. In May all 

 the indigenous species of Lecanium appear, and are then 

 often common upon oak, hawthorn, apple, etc. Early in 

 August Dacti/lopius walkeri, JSTewst., may be met with 

 sparingly behind the leaf -sheaths of Dactylis glomerata 

 and other coarse grass under hedgerows ; and towards 

 the end of the month and during September the pretty 

 little yellow male of Aspidiotus zonatus, with its black 

 apodema, may be obtained. The latest of all are the 

 curious males of Apterococcus fraxini, which emerge in 

 September and October just as the early frosts set in ; 

 but this neither lessens their numbers nor their activity, 

 as I have witnessed them searching for the female as 

 early as 8 a.m. after some three or four degrees of 

 frost. 



The males of those species infesting plants under 

 glass have no fixed period. They are most abundant 

 in summer, but may be met with throughout the year. 



In point of size those of the Diaspinse are among the 

 smallest, averaging about 1 mm. long and 2 mm. in 

 expanse of wing ; while the largest occur in the genus 

 Lecanium, and measure, inclusive of caudal appendages, 

 about 6 mm., and 4 mm. in expanse of wing. Com- 

 pared with the females they are all smaller than that 

 sex, but the disparity in size is most marked in certain 

 species of Lecanium, where the large gravid females 

 are at least from fifty to one hundred times larger and 

 heavier than the males. So extraordinary is the differ- 

 ence between the sexes in every respect, that it is 

 hard to realise they are of the same species. 



THE FEMALE. 



Diversity of form among female Coccids is very 

 great, but all are characterised by the absence of 

 wings, and there is no defined division between the 

 head and the body. With the exception of an 



