130 MACDOUGALL—ON THE LIFE-HISTORY 
Pupa.—The pupa is whitish in colour, and the 
last segment is cleft. There are long silky hairs 
down the sides and very small spines over the 
body. Length, 4 to 5 mm. 
HABITS AND METAMORPHOSIS.—There is no 
doubt whatever that R. depressus is of great ser- 
vice to the forester in assisting to hold in check 
Meats as the increase of those most troublesome enemies 
ty eg of woods, the bark- and wood-boring Coleoptera. 
ature. Two years ago I determined the shectle for a 
forester in charge of extensive woods in Aberdeenshire, and 
asked him—in connection with certain trap trees which had 
been felled and allowed to lie here and there in the pine wood 
as lures for Hylesinus piniperda, the pine beetle—to make 
frequent examination of the trees for Rhizophagus depressus. 
The trap-trees were very successful in attracting for their 
egg-laying numbers of Aylesinus piniperda, and the forester 
has just written me to say that in such trees where Rh. depres- 
sus was plentiful nearly one-half of the Aylesznus larvee were 
destroyed. 
I have taken 2A. depressus, imago and larva, from under the 
bark of Pine and Spruce; the imago moving about the borings 
and the Rhzzophagus larva (also capable of active movement) 
lying alongside the larva or pupa of the injurious species; ¢.., 
recently on removal of bark I got two Rhisophagus larve 
lying in the bed of, and attached to, a Hy/esinus palliatus pupa. 
The head of one of the larve was guurile deep in the H. pallzatus 
pupa. 
In June 1898, under the bark of some pine (Pinus sylvestrts) 
branches I found a number of Hylesinus palliatus at work, the 
mother galleries having been partly made. Each H. oye oe 
mother tunnel held two RAZ. depressus i imagines. 
_ In other two cases of grown pine and spruce, the bark in 
each case infested by /ylesenus palliatus and the wood by 
Bostrichus lineatus, 1 got numbers of Rhizophagus larve. In 
October 1898 and Pebouaty 1899, in the galleries of Hylesinus 
piniperda which held larve and pupa and dead beetles, I 
also found RA. depressus at work. 
Again, in February and March 1898, on an Austrian Pine 
