INSECTS IN RELATION TO PLANTS. 541 







sence does not in general so speedily occasion the death of the plant, as 

 the stem is a larger and less easily wounded organ than the root. 



Among the beetles we may place here the several boring and bark 

 beetles that form the family of Deperdilores (Xylotrogi, L^t.) and Bos- 

 tn/chodea ( Trogositarice, Lat.), as well as the large family of the Ceram- 

 by'cina. The majority, however, destroy the woody substance of the stem 

 in general only when the tree is felled or already prepared for manipu- 

 lation, in the latter case especially it is attacked by those of the Deperdi- 

 tores, which belong to the genera Ptinus and Anobium : they appear to 

 be created more for the dispersion of dead vegetable substances than 

 for the destruction of living plants. As Nature produces the more 

 rapid dissolution of corrupt animal matter, by means of the ontho- 

 phagous and carrion beetles, so it appears that she accomplishes the 

 same object with respect to the dead stems of plants, through the 

 agency of these insects. The larvae also of the Bitprestodea and of 

 many Elalers live in the stem, for instance, the larva- of Buprestix 

 Inguttata in the stem of oaks, Elatcr rufus in the stem of pines, and 

 both especially in the remaining stumps of felled trees. There also do 

 we particularly find the larvae of the capricorns, and living trees they 

 do not appear to care for, yet the larva of Saperda linearis lives in 

 the pith of the young tAvigs of the stem of the hazel (Coryllus avel- 

 lana), and that of -Lamia amputalor in the pith of tropical plants*, 

 that of CaUidhtm bajtdus in timber, rafters, and roofs. But the family 

 of the bark beetles (Bostrycliodea), thus named from their dwelling- 

 place, beneath the bark, are most destructive to woods, especially to those 

 consisting of firs, pines, and oaks, for example, the genus Platypus. The 

 commoner species, namely, Bostrychus typographus, B. laricis, Hyle- 

 sinus piniperda, Hylurgus ater, &c., occasionally so much undermine 

 the bark that it becomes quite loosened from the stem, and the tree, 

 having lost in its liburnum its nutritive layer, dies. Formerly many 

 instances occurred of whole forests of pines being thus destroyed in the 

 Harz, in Franconia, and in Silesia, and it was called the (wurmtrocknisz; 

 worm dry rot. Tropical trees are also visited by such guests, for 

 instance, the stems of palms by the Calandra palmar urn, but they are 

 chiefly found in felled trees lying in the woods, and which they speedily 

 destroy through the great size they attain. It is thus also that the large 

 larvae of exotic capricorns live, as those of Prionus cervicprnis, Pr. 



* Lansdown Guildinz in I.innaean Trans, vol. xiii. 



