206 
ROBINIA PSEUDACACIA. 
that had been blown down by a storm, which were much bored by the larvse of 
these insects, with their heart- wood dead. In splitting some billets of these trees 
he found that they contained several of the cater- 
pillars or borers, of different magnitudes, which 
enabled him to watch them through the various 
stages of their growth. " The furrows in the bark 
of the locust," says he, "are large and deep, ex- 
tending, in some places, even to the liber or inner 
bark. It must be in the deepest of these furrows 
that the egg to produce the caterpillar is deposited. 
The inner bark is thick and succulent, affording to 
the young larvse a tender and proper food. The 
sap-wood is harder; this, too, is perforated to theQ*^*^ 
perfect, or heart-wood, on which it is afterwards to 
feed. This it bores in various directions, obliquely, 
upward, and downward, making them larger as it 
increases in bulk. Some of these perforations are ^ 
large enough to admit the little finger. The grubs 
of the wood-eating beetles always provide a path for the escape of the perfect 
insect out of the wood, before they go into the nympha or chrysalis state'. In 
the same manner does the caterpillar of the locust form an opening quite through 
the bark, before it forms its cocoon. An inspection of the scene of its labours, 
clearly discovers how everything is done." Professor Peck supposed that the 
larva lives in the wood three years or more, before it attains its full groAvth. 
The moths, which come forth about the middle of July, have thick and robust 
bodies, broad, and thickly veined wings, two distinct feelers, and antenna?, that 
are furnished on the under side, in both sexes, with a double set of short teeth, 
rather longer in the male than in the female. The larva of this insect is said 
also to prey upon the wood of the black oak (Quercus tinctoria.) The other 
insects that attack the common locust-tree, is a species of apion, which inhabits 
the pods and devours the seeds ; and the Eudamus tityrus, which feeds upon its 
foliage, as well as upon that of the Robinia viscosa. 
Properties and Uses. The wood of the locust, which is commonly of a green- 
ish-yellow colour, marked with brown veins, is very hard, compact, and suscep- 
tible of a brilliant polish. It possesses great strength, with but little elasticity ; 
and its most valuable property is that of resisting decay longer than almost any 
other species of wood. When newly cut, it weighs sixty-three pounds, three 
ounces to a cubic foot ; half dry, fifty six and a quarter pounds, and when quite 
dry, only forty-eight and a quarter pounds, or according to others, only forty- 
six pounds. According to M. Hartig, the German dendrologist, its value for fuel, 
when compared with that of the beech, (Fagus sylvatica,) is as twelve to fifteen. 
For duration, he places it next below the oak, (Quercus robur,) and next above 
the larch, (Larix europgea,) and the Scotch pine (Pinus sylvestris.) Barlow, 
in Wither's "Treatise," gives the strength of locust timber, as compared with 
other woods, as follows : 
Teak, (Tectona grandis,) 2462 
Ash, (Fraxinus excelsior,) 2026 
Locust, {Robinia pseudacacia,) 1867 
Oak, (Quercus robnr,) 1672 
Beech, (Fagus sylvatica,) 1556 
Norway spar, (Abies excelsa,) 1474 
Riga fir, (Pinus sylvestris rigensis,) 1108 
Elm, (Ulrnus campestris,) 1013 
