1907.] 



Wood Wasps, 



101 



ready, continues the tunnel and gnaws with its mandibles a 

 circular exit hole. In observing the exit I have been struck by 

 the mobility of the head and the skill in making the hole. 



Speaking generally, issue of adults hikes place from the 

 summer onwards. I have from different material in different 

 years bred out the adults in late July, August, and September. 

 Wood split in November has revealed live wood wasps which 

 might possibly have issued in the next spring. 



Wood wasps most assuredly often issue from timber imported 

 into our country, but both species breed freely in our own 

 timber. I have had the giant wood wasp from Devon, Norfolk, 

 Anan, Perthshire.. Midlothian, East Lothian, and a further 

 record from Durham. The late Miss Ormerod had it sent to her 

 from several Irish counties, and Mr. Theobald has recorded it 

 from North Wales. Specimens of the steel-blue wood wasp have 



LARVA OF Sirex gl'gas, IN TUNNEL GNAWED IN WOOD. 



been sent to me from Aberdeen, Perthshire, Midlothian, Ayrshire, 

 Peebles, Glamorgan, Suffolk, Kent, and Galway. 



The time taken for the life-cycle from egg-laying to issue of 

 adults will wiry with the conditions — temperature, character of 

 material, \v. — but in all probability the generation never takes 

 less than two years, and it is often longer. Adult wood wasps 

 have issued from worked timber in houses and factories, wood- 

 work and plaster and lead pipes all having been bitten through. 

 The appearance of the buzzing adults in inhabited rooms — wthe 

 insects having completed their development in wood-work m 

 the room — has more than once been the cause of alarm. I 

 received a number of steel-blue wood wasps which had thus 

 issued from the tlooring of a smithy in Lockerbie. The tlooring 

 had been laid in November, 180,8, cut from timber that had 

 been lying in the open for .1 long time. The wood wasps issued 

 in July, 1899, and more in September, 1900. 



Wood wasps prefer old stems for their egg-laying. Pole 



