OVIPOSITION AND THE EGG OF LTCTUS BEUNNEUS. 219 
of 8° C. to retard development ; this material was withdrawn in July 
1920 and enabled the writer to verify the observations on oviposition and the 
■egg at leisure. 
The infested woods collected were West African mahogany [Kliaya sp.), 
"" Wainscot ■" oak (^Quercus Rohur), and " Italian ■" walnut (Juglans reffia). 
Beetles were also bred from locust (Robinia pseudacacia). 
Unfortunately no living specimens of L. linearis were obtained, although 
-efforts were made in various directions to procure some. No beetles emerged 
from two pieces of oak — hitherto infested with L. linearis — which were sent 
over from Paris, nor were any living larvse or pupae found. Dr. C. J. Gahan 
informed the writer, that no record of the capture of this beetle in the British 
Isles had come to his notice for some years. 
Mating. 
The beetles are sexually mature when they emerge. Mating takes place 
immediately after emergence either at dusk or during the night. It was 
observed in daytime ; and on several occasions two beetles were found 
occupjdng the same pupal chamber, but in no instance was mating observed 
to last very long. Individual males fertilize several females, therein differing 
from L. lineaj'is as described by Xambeu (1898), who stated coition lasted 
the entire night and the male then dies. In hrunneus, females considerably 
outnumber the males. 
The length of the life of the females when free to mate and oviposit 
avei'aged about six weeks ; the males lived two to three weeks. The food of 
••the adults consists of particles of wood-tissue. 
Oviposition. 
The ovipositor is an exceedingly long and flexible organ, and when fully 
extruded (PI. 12. fig. 1) it is nearly the length of the beetle. 
Oviposition begins two to three days after mating and takes place, at dusk 
or during the night, in the trachese, or vessels, or pores of the wood. 
•Consequently those woods in which the vessels are most numerous are most 
liiible to heavy attacks. 
The female either projects the ovipositor directly into the vessel, or it is 
curved down and bent forward in the vessel underneath the body. Before 
■actually inserting the ovipositor into a vessel, a preliminary examination of 
the surface is made with the ventral pygidial palps, and after selecting a 
vessel the ovipositor is slowly inserted, and apparently a further examination 
is made within the vessel bj' the vaginal palps (p, text-fig. 1) on the apex 
of the ovipositor ; when, if the conditions are suitable, two or more eggs are 
deposited. The number, however, depends upon the suitability and capacity 
of the vessel. For, when an obstruction is encountered — in the form of 
broken down transverse walls, etc. — only one or two may be deposited, or the 
ovipositor will -be withdrawn and another vessel tried. 
16* 
