VI PREFACE. 



(3) Winter Visitors, which visit us in winter, but do not 

 breed here. 



(4) Occasional Visitors, which are only of irregular occur- 

 rence, but are met with in our islands with more or 

 less frequency. 



It is in many cases difficult to decide in which of these 

 four divisions a particular species should be placed ; but the 

 Table on the next page is believed to give with tolerable 

 accuracy the number of species, in each of the seventeen 

 orders, members of which occur in the British Isles. 



P. L. S. 

 H. T. W. 



April 3rd, 1883. 



