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others. The Rook, for instance, is a bird concerning 

 which it is at present impossible to say whether it is a 

 beneficial or harmful species. It consumes a vast amount 

 of grain but, on the other hand, during the summer it 

 devours a great many injurious insects of various kinds, 

 including both leather- jackets and wireworms. The 

 Starling also devours a large amount of grain during 

 certain times of the year, but this appears to be com- 

 pensated by the great quantity of injurious insects which 

 the bird consumes at other periods. As many as 197 

 leather- jackets, for instance, have been found by Mr. 

 Leigh in the crop of a single bird. The Chaffinch is by 

 no means as destructive as is commonly believed. It 

 consumes large quantities of seeds of such troublesome 

 weeds as, dock, knotgrass, hawkweed, and especially 

 chickweed. Mr. Leigh informs me that although he 

 found grain in the crops of 41 per cent, of the birds which 

 he examined, it appeared to have been taken in most cases 

 from manure or ricks in farmyards and not from culti- 

 vated land. It must be further added that evidence 

 points to the fact that the majority of species of birds 

 feed their nestlings on soft-bodied insects and other 

 invertebrates. Consequently even the most destructive 

 birds may perform a useful function during that stage in 

 their life. 



EELWORMS (4), (5), belong to the group of the Nema- 

 toda. They are always small in size and have thread-like 

 bodies, the two ends being more or less pointed. They 

 can be readily distinguished from the Oligochaeta or 

 Earthworms by the total absence of body rings or seg- 

 ments. Those which are plant parasites are microscopic 

 forms living free in damp soil or inside the tissues of 

 plants. Others live in decaying vegetation, and both the 

 parasitic and saprophytic forms can be recognised by the 

 presence of a spine which can be protruded through the 

 mouth and serves to penetrate the cell-walls of plants. 

 The Eeiworms spread from one plant to another by 

 wandering through the soil, and when they leave the dead 

 plants they lie near the surface of the ground. Fre- 

 quently when these animals are numerous it is useless to 

 grow susceptible plants in the same patch of soil during 

 successive seasons, and then as long an interval as possible 

 should elapse between the growing of two crops of the 

 same plant. The STEM EELWORM (Tylenchus devastatrtx, 



