TIMBER TRANSPORTERS 469 



And Mr. A. T. Gillanders relates " that one of the best 

 consignments of those insects I ever had sent me was 

 captured by a miner, issuing from props within the coal-pit." 

 Most pit-props are imported from Norway. 



TIMBER CARRIES BORING CREATURES 



No set of imported animals is more characteristic than 

 the timber transportees. They are almost without exception 

 creatures whose larvae bore in the solid wood of trees, and 

 on this account their kind is mainly limited to Sawflies, 

 such as the Wood- Wasps, and to Beetles, particularly of the 

 boring Longicorn group. In addition, parasites may be 

 carried in the Wood- Wasp or Beetle larvae, and thus foreign 

 Ichneumon flies may emerge on our side of the ocean. 



A FEW EXCEPTIONS 



There are at least two striking exceptions to the rule 

 that timber carries only boring creatures. I have seen two 

 specimens of theblack and blue, yellow-banded shining lizards 

 known as Blue-tailed Skinks (Eumeces quinquelineatus}, 

 which a few years ago accompanied a cargo of timber to a 

 Musselburgh timber-yard. The timber had been imported 

 from North America, where, in the United States, the Blue 

 tailed Skink has a wide range. It has a habit of concealing 

 itself under the loose bark of trees, and this no doubt led to 

 its long and involuntary journey. 



It is unlikely that the Blue-tailed Skink would have 

 established itself in this country, for even in North America 

 its range is limited ; but another rather unexpected intro- 

 duction with timber has met with greater success. 



In 1824, the Linnean Society received the first recorded 

 British specimens. of the Zebra Mussel (Dreissensia poly- 

 morpha), these having been found in abundance attached to 

 shells and timber in the Commercial Docks on the Thames. 

 The Zebra Mussel lives in fresh water, in the Danube and 

 the rivers of Russia, and in northern France, Belgium and 

 Germany. It is supposed to have been originally carried to 

 Britain with cargoes of wood from the Volga, and it has 

 actually been seen attached to Baltic timber ere yet the 

 timber was removed from the ship's hold. The success of 



