THE FEMALE. 13 



completing the second stage. The gravid female in 

 life has the whole ventral surface very closely adhered 

 to the portion of the plant upon which it is fixed ; but, as 

 the insect matures and egg-laying proceeds, the ventral 

 surface with the exception of the extreme margin 

 gradually shrinks until it meets the hardened outer 

 skin. Thus the insect becomes a hollow hemisphere 

 filled with eggs, which her dead body continues to 

 protect until the young are hatched, and long after- 

 wards remains attached to the food-plant as an empty 

 shell. This remarkable shrinking process is much less 

 marked in the flat species of Lecanivm; in the first 

 place there is comparatively little to shrink, but a 

 slight cavity is formed sufficient to protect the few 

 young that are generally produced. 



The indigenous species of the hemispherical type of 

 Lecanium are generally brightly coloured, possessing a 

 nuptial dress of shaded reds and crimsons traversed 

 by ivory-white markings, which renders them more 

 like galls or berries than living insects. Those of the 

 hesperidnm and coryli type are remarkable for the 

 abnormally long periods of fertility they are able to 

 sustain, generations succeeding each other fpr years 

 without the intervention of a male. Several species 

 have been under continuous observation for many 

 years without any trace of a male having been seen. 



The genus Pulvinaria is very closely allied to 

 Lecanium, so much so that it is scarcely possible to 

 separate either the larva or adult until the period of 

 parturition commences, when a white pad of wax is 

 secreted behind and beneath the body of the female, 

 which alone gives the key to the genus. 



In its larval stage, PhysoJcermes alrietis is also very 

 closely allied to Lecanium, but the adult has neither 

 legs nor antennae present, and is otherwise a very re- 

 markable insect. 



Both British species of Lecanopsis are subterranean ; 

 L. formicarnm is found associated with ants, but, from 

 its rarity, very little has been learned of its economy. 



