LECANIVM CAI'IU^E. Ill 



May. At this period the females (figs. 2-2 b) have 

 attained almost their maximum size, and the strongly 

 contrasting colours render them very conspicuous. 

 Egg-laying takes place at the end of May and early 

 in June, and the number laid by a healthy female aver- 

 ages about 2000. In all the colonies I have seen there 

 is a preponderance of females, but the male puparia 

 may be found in considerable numbers in large 

 colonies. 



These insects are much subject to the attacks of a 

 small hymenopterous parasite (Blastotlirix sericea, 

 Dal.), which is its chief enemy. The remarkable effect 

 which these parasites produce on the external form of 

 the insect has already been described. Professor 

 Cockerell has noticed very similar malformations to 

 those of var. a in a North American species of 

 Lecanium, and I have received specimens from Austria 

 very similar to the var. )3. Not only is there an altera- 

 tion of form caused by the parasites, but the colour is 

 also changed generally to a more or less uniform 

 fuscous or yellowish colour. 



In sheltered hedges of hawthorn this species is 

 sometimes extremely abundant, so much so that I have 

 known it to kill large patches of a hawthorn hedge 

 skirting the borders of this city (Chester). Their 

 ravages were particularly noticeable in the year 1890, 

 when they certainly attained their maximum in 

 numbers. Since that time they have gradually de- 

 creased through the attacks of natural enemies both 

 of birds and insects, more especially the latter. On 

 large isolated trees they generally occur singly upon 

 the terminal branches, and the sexes are often widely 

 separated ; in such cases it is highly probable that the 

 females are rarely fertilised. 



In describing this species I have confined myself 

 entirely to a single colony of insects on hawthorn 

 (Cratdegus oxyacantlia), in order to show that this 

 species possesses all the varied characters set forth by 

 former students of the group, which, I think, thoroughly 



