GIANT SIREX. 69 
Giant Sirex; Yellow Fir Wood Wasp. Sirex giyas, L. 
Common Steel-blue Sirex. 
SIREX GIGAS.—Female ‘‘Wood Wasp” and maggot. Jaw of maggot, with four 
sharp, narrow teeth ; and jaw of fly, with three broader teeth—both magnified. 
The damage caused by the great grubs of the large four-winged 
Sirea flies to living Fir timber of various kinds is probably much more 
commonly present than is generally known, for though in the past 
twenty years I have only in three (namely, in 1878, 1889, and 1890) 
had important enquiries sent regarding cause of the damage, yet speci- 
mens of these ‘‘ Wood Wasps,” and especially of the large black and 
yellow-banded kind figured above, and known as the ‘‘Giant’’ Sirex, 
are frequently sent me with a request for the name. 
The dark blue Sirex, scientifically Sire juvencus, is known as the 
‘‘Common”’ Sirex, but, excepting in the year 1890, I have very rarely 
had observations of this species, and in the year named, curiously 
enough, all the observations sent of harm done were from workings of 
this species. The greatest damage reported was to about forty Silver 
Firs on a property near Whitehaven, Cumberland, of which three- 
fourths were said to be practically dead, ‘‘ the residue in a moribund 
state.’? The trees were over seventy years of age, and the damage was 
estimated at a little over 1200 cubic feet of timber irretrievably ruined. 
In a block of damaged wood measuring fourteen inches in length by 
eight in diameter, thirty-three perforations were counted from which 
perfect insects had made their escape. 
In regard to the Sirea gigas (figured above), in 1878 several trees 
some miles apart near Dalkeith, N.B., were found to be badly infested 
by it; one of these (a fallen Spruce Fir) was found to be ‘‘ swarming”’ 
full of it. But the worst infestation I have seen myself came under 
my notice at Sedbury Park in West Gloucestershire. I noticed speci- 
mens on the wing there during many years whilst still resident there 
