Insects Bred from American Larch 99 
Rhyssa lineolata Kirby. 
(Det. by S. A. Rohwer) 
According to Merrill (1915, p. 147) the geographical 
range of Rhyssa (persuasoria) lineolata is very wide, extend- 
ing “ Through Europe to Canada and the United States in 
the West, and the Himalayas in the East.” Merrill (loc. 
cit., pp. 144-147) has reviewed at some length what is known 
regarding the habits of this species and it seems undesirable 
to repeat this here. It has been reported as parasitic upon 
Sirex spectrum, Sirex (Urocerus) cyaneus and Monoham- 
mus, while other species occurring in Europe are parasitic 
upon several species of Xyphydria. 
In our larch material there can be no doubt that R. lineo- 
lata is parasitic upon Phymatodes dimidiatus. The reasons 
for this statement have been cited on p. 32 and seem conclu- 
sive. The fact that cocoons large enough to have served the 
pupa of R. lineolata and Pseudorhyssa sp. occurred only in 
the burrows of P. dimidatus and that no cocoons of any sort 
were discoverable in the mines of S. barbatus, the only other 
insect common to the three lots of material would seem to 
be conclusive. Of the three lots from which this parasite 
was bred only one gave rise to any siricids, U. albicornis and 
S. abbotwu being obtained from this lot, and an investigation 
of their burrows showed the entire absence of parasitic 
cocoons. 
While we cannot state too strongly our certainty that R. 
lineolata in our material was parasitic upon P. dimidiatus, 
we do not in any sense wish to cast discredit upon observa- 
tions which have shown it to be probably parasitic upon 
quite different insects. Indeed, it is nearly certain that this 
species is parasitic upon many wood and bark-boring forms. 
In fact, the senior author has removed an adult from the 
wood of hemlock where it was associated with adults of 
Urocerus albicornis and with larvee and pupee almost cer- 
tainly belonging to the same species. As the adult parasite 
which was alive and ready to emerge was removed from a 
burrow similar in all respects to those from which the speci- 
