Insects, etc.. Injurious to Currants. 235 



The adult stage is reached after a series of moults, but the exact 

 number of these has not been ascertained. 



The different stages vary to some extent in shape, some being 

 slightly longer and narrower than others, while many are very short 

 and stout, presenting a swollen appearance towards the head. They 

 seem capable of contraction and expansion, and this partly accounts 

 for the difference in form. The eggs (Fig. 178) are very large when 

 compared with the size of the mite ; they are pale greenish in colour 

 and glassy in appearance, furnished with a strong chitinous covering 

 which becomes irregular in shape (according to Lewis) just previous 

 to the hatching of the mites. 



LiFE-HlSTOEY AND HaBITS. 



Writing in the S. E. Agricultural College Journal, Mr. Lewis 

 said : " The life-history of the mite does not up to the present seem 

 to have been quite satisfactorily determined. The question as 

 to what happens to the mite when the buds burst in the spring 

 and summer has not been satisfactorily answered in a manner 

 to account for the continuance of infestation in certain cases, 

 where drastic measures have been resorted to with a view to ex- 

 termination. The fact that the whole of the diseased bush above 

 ground can be cut down and destroyed, and the root stock also 

 subjected to treatment without result (all the bushes in a diseased 

 plantation being treated alike), seems to show that the mites, 

 or their eggs, or both, must be able to retain their vitality for a 

 considerable period in the soil. I have, however, never- yet found 

 any mites living for any length of time in the soil taken from 

 around infested bushes, after subjecting samples to careful micro- 

 scopical examination. The minute size of the mite makes it a 

 very easy matter to pass it over, even after exhaustive search, 

 and this applies as much or more to the eggs also, but if living 

 mites continued to be present in any numbers, some at least ought 

 to have been found in the numerous samples of soil taken. The 

 margin for error is, however, too great in such a case for a reliable 

 and definite result to be obtained." Eepeated examinations have 

 definitely proved that eggs may be present in the buds all the year 

 round, but more numerous at some seasons than others, and 

 regulated in numbers to a large extent by temperature. There are 

 fewer in December and January (especially in the latter month), 

 according to Lewis and my own observations, than at any other time 

 during the year. The fact of the presence of the eggs in the buds 

 throughout the year is a very important one, and has been questioned 



