102 First Report on Economic Zoology. 



predaceous insects as if they would do all that is required to check 

 an insect pest. In a few cases predaceous insects have done 

 enormous good, under abnormal conditions, but in a state of nature 

 they never appear in sufficient numbers to make any impression 

 until the pest in question has increased to such an extent that the 

 harm is all done. The introduction of new predaceous forms is, 

 however, always worth trying, as now and again good has resulted, 

 as seen in the case of the Icerya scale and Vedalia cardinalis. 

 When people commence to talk of stopping spraying for Aphides 

 or scales because the beneficial parasites are killed also, it is sufficient 

 evidence they know little of fruit-growing or the fruit grower's 

 troubles. 



In the Tipulidpe we find scarcely any record of insects that 

 destroy either larvpe or adults. Curtis mentions Ichneumons as 

 attacking the larva, but says no more. Although I have bred large 

 numbers from different parts of Britain I have never come across a 

 parasite, with the exception of a single ? Tacliina, sp. (?) that appeared 

 in a cage of T. olcracca. Numerous birds, however, feed very largely on 

 these insects, not only upon the larvae, but also upon the adult flies. 



Amongst those birds which are great " leather-jacket " destroyers 

 are the following : the Kook, the Starling, the Peewit, various Gulls, 

 the Pheasant, and, to a lesser extent, all the Turdidce, or Thrushes, 

 and Blackbirds. Enormous numbers of these larvae are devoured in 

 autumn, winter, and spring by the three former birds, and the 

 pheasant's crop may frequently be found full of them. The decrease 

 iti the number of Peewits has been marked by a corresponding 

 increase in this pest as well as in the Wire-worm. All these birds 

 sjiould be encouraged, not only because of then- destroying "leather- 

 jackets," but other pests as well. 



The adults are devoured by the Spotted and other Fly-catchers, 

 by the Swallow, and even by the Sparrow. The Piook also devours 

 large numbers as they are ovipositing in the fields. Poultry also do 

 much good, for they feed whenever opportunity occurs upon both 

 larvffi and adults. These birds all do good because they are always 

 present and are constantly feeding. They are often attracted in greater 

 numbers when hosts of insects appear, but even when normally present, 

 by devouring these and other pests before many of them have done 

 harm, they do inestimable good, whilst on the other hand parasitic 

 and predaceous insects come too late. 



Moles also feed off leather-jackets, and do far more good than 

 harm even in pasture land, where their " heaps " cause some 

 inconvenience. 



