THE OAK-PRUNER. 



83 



The callosities on the segments, as figured in the cut, are prominent, more or less 

 rounded tubercles -with the surface divided irregularly by impressed lines. 



Length, 3r)">'" ; width of prothoracic segment, 8'"'" ; length, 3™"i ; length of a leg 

 with terminal claw, 0.4"^"' ; length from base of labrum to posterior edge of meta- 

 thoracic segment, 5'"'"; length of first and second abdominal segment, each, 2™"^; 

 length from base of third abdominal segment to end of body, SS""" ; width of each of 

 segments 2 to 6, 6™'" ; the seventh and eighth segments are slightly wider. 



Found in an oak log at Providence, R. I., May 20, I8dl. 



Compare also pi. xvii. Fig. 2; xix, Fig. 2; xx, Fig. 3. 



AFFECTING THE LIMBS AND TWIGS. 



28. The oak pruner. 



Elaphidion villosum (Fabr. ). 



Order Coleoptkra; Family Cerambycid^. 



Cutting off the branches of the white and black oak, which fall late in summer to 

 the ground, containing the larva, which becomes a beetle in the next midsummer 

 and lays its eggs near the axilla of a leaf stalk or small stem. 



In walking uuder oak trees iu the autumn one's attention is often di- 

 rected to tbe large number of oak limbs and twigs lying on the ground. 

 Upon examination they will be found to have been partially gnawed off 



Fig. 31.— Oak pruner: a, larva; 6, side view of the same; c, pupa.— From Packard. 



by worms, the wind having further broken them off. This is the work 

 of the grub of the oak pruner. The insect's purpose in cutting off the 

 limb, whether conscious or not of any design in the matter, is probably, as 

 Peck first suggested, to atlord the insect a sufficieutly moist retreat to 

 live iu during the winter. He supposed that the limb thus wounded 

 would become too dry for the maintenance of the soft-bodied larva, 

 hence it must be felled to the ground, where iu the wet and under the 



