492 



COLEOPTERA. 



47:5. 



rounded beetles of an elongate cylindrical form, truncated be- 

 fore and behind. They mine under the bark of trees, running 

 their winding galleries in every direction. They rarely attack 

 living healthy trees. They are usually brown 

 or black in color. The rounded head does not 

 j end in a snout and is deeply sunken in the 

 thorax ; the clavate antennae are somewhat el- 

 bowed, while the palpi are very short ; the 

 elytra are often hollowed at the end, and 

 the short stout legs are toothed on the under 

 side of the femora, and the tarsi are slender and 

 narrow. The eggs are laid in the bark, whence the larva? on 

 being hatched bore straight into the sap wood, or mine between 

 the bark and sap wood. They are like those of the preceding 

 family, fleshy, cylindrical, footless larvae, wrinkled on the back. 

 When fully grown in the autumn they gnaw 

 an exit for the beetle, taking care to leave a 

 little space closed in front of their burrow to 

 conceal the pupa. The bark of trees infested 

 by them should be scraped and whitewashed. 

 Hyluryus terebrans Oliv. (Fig. 474) is a rather 

 large red species, very abundant in spring. 

 It is found under the bark of pines associated with Pissodes, 

 though the larva is smaller and more cylindrical. It mines the 

 inner surface of the bark, slightly grooving the sap wood, and 

 pupates in April, appearing as a beetle in great numbers on 

 warm days early in May. Hylurgus dentatus Say 

 infests the cedar. 



The Scolytus destructor of Olivier often does much 

 injury to old and deca^ying elm trees in Europe. 

 Capt. Cox exhibited to the Entomological Society of 

 London a piece of elm three feet long, which was 

 scored by the lateral tubes of this insect, which he 

 estimated must have given birth to 280,000 larvae. 

 The various species of Scolytus, Tomicus and Xyloterus give 

 rise to a disease similar to fireblight, by their ravages beneath 

 the twigs of fruit trees, causing the bark to shrivel and peal 

 off as if a fire had run through the orchard. The best method 

 of restraining their attacks is to peal off the affected bark, ex- 



rig. 474. 



