588 The Black Currant Gall-Mite. [Jan., 



noticed on the stems so late as September 20th in 1901, Sep- 

 tember 14th in 1902, and October 28th in 1903. During the 

 migration period thousands of mites fall off the branches to 

 the ground, many are distributed by birds, insects, arachnids, 

 leaves, &c., to other bushes, the remainder dying. 



It has already been pointed out that about the middle of 

 June eggs and mites in various stages of development are to 

 be found in the centre of the new buds. During the winter of 

 1902-3 one or more buds were examined once a week from 

 September to March, and in nearly all cases eggs were found to 

 be present. They were certainly very few in number from 

 December, 1902, to March, 1903, and it seemed to m.e that 

 many of them were dead. From October 14th, 1903, to 

 January 30th, 1904, buds were taken from another tree and 

 examined once a week, but, in spite of the most careful 

 searching, no eggs were discovered after October. 



The newly infested buds commence to swell and become 

 irregular in shape towards the end of August or the beginning 

 of September. 



The dates of appearance, migration, &c., for the years 1899- 

 1906 may be summarized as follows : — 





1899. 



1900. 



1901. 



1902. 



1903. 



1904. 



1905. 



1906. 



Eggs found ... 







All the year round (see paragraph above). 





Mites appear ... 



"( 



Mar. 



Mar, 



Mar. 



:\Iar. 



Mar. 



Mar. 



Mar. 



Mar. 



\ 



26th 



•20th 



24th 



28th 



26 th 



28th 



22nd 



20th 



Old infested buds 



















dry up 





May 



May 



May 



May 



May 



May 



May 



May 



JVIigration com 



1 



/ 



April 



April 



April 



April 



April 



April 



April 



April 



mences 



19th 



12 th 



30th 



26th 



loth 



20 th 



13th 



Migration ceases . 









Middle of June 























Mites found in new 1 





June 



June 



June 



June 



June 







buds 



/ 





19th 



14th 



8th 



21st 



6th 







Eggs in new buds 



f 

 1 





July 

 2nd 



June 

 28th 



June 

 19th 



July 

 3rd 



July 

 1st 







Mites last seen 



{ 



1 



Sept. 

 4th 



Sept. 

 18th 



Sept. 

 20th 



Sept. 

 14th 



Oct. 



28th 



Oct. 

 4th 







New buds com- 



Sept. 



Sept. 



Aug. 



Sept. 



Sept. 



Sept. 







mence to swell 



/ 



20th 



10th 



28 th 



20 th 



14th 



7th 







The number of stages which the mite passes through is not 

 definitely known ; there are certainly two before attaining the 

 adult condition. 



MetJiods of Distribution. — The ordinary method of loco- 

 motion is by crawling, and this is carried out by means of two 

 short pairs of legs and with the aid of the tail. As was first 

 pointed out by Mr. Warburton* the mites are often to be seen 



* op, cit., p. 371, 



