NOTES AND QUERIES. 253. 



the oviparous group of the sub-family Tachininae, and is 



extremely prolific. Neilson, a Danish authority, observed 



twenty-three eggs laid on a single Hyponomeuta caterpillar, 



but from these eggs only one parasite attained maturity. 



According to Baer there are at least two generations in the 



year — the adults fly especially from May till June, and again 



during September and the beginning of October. The 



maggots, on emerging from eggs laid on the skin of the 



caterpillar, bore their way into the organs of the host and 



there feed and grow at its expense. Finally, when full grown 



the parasite leaves its host in order to pupate, and after a 



pupal period of a fortnight the adult Tachinid issues. 



There is no doubt from the experience at Kew that P. selecta 



is an important natural enemy of T. viminalis, and that it plays 



a very useful part in controlling this saw-fly and so preventing 



extensive damage to young poplars. 



R. C. F. 



Dryocoetes alni (Georg.) : An Alder Bark Beetle 

 (Scolytidae) new to Scotland. 



While collecting in the neighbourhood of Cockburnspath, 

 Berwickshire, in September 192 1, I took several specimens of 

 this beetle from under the bark of dying alder trees overhanging 

 the banks of a small stream near the sea-shore. So far as 

 I can ascertain from published records, this is the first 

 time the species has been collected in Scotland, and, according 

 to Fowler, even in England it is rare, although recently it 

 has been taken by Professor Beare, in considerable numbers, 

 near Kidderminster. This species is recorded by Reitter 

 as occurring in several species of alder on the Continent, 

 while in England it has been taken on beech and alder. I 

 found signs of its presence only on two trees, and while 

 traces of the galleries were present, no larvae or pupae were 

 seen, and time did not permit of any study being made of its 

 life-history and further distribution. 



One other species of this genus is known to occur in 



Scotland, D. mitographus, Ratz., which is found on the fallen 



stems and trunks of spruce. 



R. N. C. 



