20G BOBINIA PSEUDACACIA. 



that had been blown down by a storm, which were nnich bored by tlie larva: of 

 these insects, with iluir heart-wood dead. In splitting some billets of these trees 

 he found that they conlaiiu'd scvt-ral of the cntor- 

 pillars or l)orcrs, of dilliMcnt niauiiitudcs, which 

 enabled him to watch them through the varions .^ ^ 



stages of their s^rowth. " The fnrrows in the bark ./,^^* 



of the locust, "''^ays he, "are large and deep, ex- .--'S'^i^l, /.-iii// 



tending, in some places, even to the liber or nmer X^'^P-ril^'J^ 



bark. It must be in the deepest of these furrows, //z;^ V'V. V^ 



that the es:g to produce the cateri)illar is deposited. LMrT)p _- 

 The inner bark is thick and succulent, affording to yOfc^'^^^' '* 

 the young larva? a tender and proper food. The /vj^ly^'j/''^^^A< 't\'h 

 sap-wood is harder; this, too, is perforated to thei^^]^^^^ \ 'u^ 'vj 



perfect, or heart-wood, on which it is afterwards to ~*~^* 



iced. Tiiis it bores in various directions, obliquely, ^ , , ^ 



upward, and downward, making them larger as it ^^*fifW.,K7"vXTr?7**i^^^ 

 increases in bulk. Some of these perforations are -Mm'^ 



large enough to admit the little finger. The grubs ^^L. ^ ^ * - -^^^^ 

 of the wood-eating beetles always provide a path for the t Mupe of the perfect 

 insect out of the wood, before they go into the nymplia or chrysalis stale. In 

 the same manner docs 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 growth. 

 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 apiojij 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 europaea,) 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, {F?^axmus excelsior,) 2026 



Locust, {Robinia pseifdacacia,') 1867 



Oak, {Querc7is robur. ^ 1672 



Beech, {Fagus sylvatica,) 1556 



Norway spar, {Abies excelsa,) 1474 



Riga fir, {Finns sylvestris rigensis,) 1108 



Elm, {Ubnus campestris,) 1013 



