322 PROTECTION AGAINST INSECTS. 



d. Protective Rules. 



Mix broadleaved trees with Scots pine. 



Protection of enemies : Fox, badger, hedgehog, shrew, cuckoo, 

 crow, starling, thrush, titmice, golden-crested wren, etc. 

 Calosoma sycophanta, L., is very useful on the Continent, and 

 many parasitic insects and fungi attack the larvae. 



Fungi (Empusa sp.) killed nearly all the caterpillars in the 

 Tuchler Haide in 1867, their bodies being covered with 

 yellowish-grey sporangia, which after rain became dark brown. 

 The infected caterpillars were brittle like the pith of elder, and 

 filled internally with a yellowish substance. 



e. Remedial Measures. 



i. Pigs may be admitted to the woods from July till hard 

 frost sets in. In the forest district of Cloppenburg in Olden- 

 burg in 1845, 58 pigs in 29 days (November and December) 

 are estimated to have destroyed 16,000,000 pupae. 



ii. Caterpillars may be collected from the middle of May 

 onwards by beating the stems, or in July by picking them 

 from lower growth, or at the foot of the stripped trees, where 

 they often collect in numbers. 



iii. Pupae may be collected during the winter, under moss, 

 etc. ; the holes whence stumps have been extracted should be 

 specially examined. 



iv. Moths may be collected by striking the trees in cloudy 

 weather or by " sugaring." 



Trenches are not of much use, as the caterpillars are little 

 given to wandering about. 



2. Noctua (Agrotls) restigialis,* Eott. 



a. Description. 



Moth with an expanse of wing of 80 to 35 mm. Fore-wings 

 ashy grey, mingled with brown, variable in depth of colour, 

 with fine black veins, the three stigmata conspicuous, darker 



* Larvae of the different species of Agrotis usually live in the ground; they 

 gnaw through plants above the roots, a.nd in America are appropriately termed 

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