FRUIT-TREE BARK BEETLE. 



199 



Work of S. ru- 

 gulosus in Apple- 



The accompanying figure of an infested Apple-twig, with 

 part of the bark removed, shows injury just underlying the 

 bark in irregular workings and perforations 

 through the bark.* Tlie beetle is of the shape 

 figured, magnified, at p. 197, and shining, but, 

 on account of its wrinkled surface, not so much 

 so as the rather larger kind the Scolytus pruni. 

 The fore body is extremely closely covered 

 with deep oblong punctures, confluent into 

 wrinkles in front and at the sides. The colour 

 is black, with tips of the wing-cases, horns, 

 and legs, or a portion of them, red or reddish 

 brown ; the wing-cases have punctures on the 

 interstices as large and deep as those in the 

 striae. The length of the beetle is about the 

 tenth of an inch ; and the abdomen is shorter 

 than the wing-cases. 



The larva, figured at heading, is white, with 

 small yellowish head, and brown mandibles, 

 and surface wrinkled. The pupa is also white. 



According to Dr. Taschenberg, the develop- 

 ment of the beetles from the first-laid eggs is twig; natural 'size, 

 completed by the end of June. This agrees 

 with the state of the specimens sent me by Mr. Newstead. Of 

 these, on June 21st, I found the beetles had been developing 

 numerously. The dust which had dro|)ped from their work- 

 ings induced me to make a careful examination as to what had 

 been going on, and at first only a few of the beetles were 

 noticeable in the box ; but, on moving the pieces of infested 

 branches, I found that numbers of them were present, running 

 about fast and actively. 



With regard to the number of successive broods that there 

 may be in one year, this appears, from the comparison of 

 observations given in Mr. Chittenden's paper previously 

 noticed, to depend very much on climate. Formerly it was 

 supposed by continental observers that there was only one 

 generation annually ; now it is known by U. S. A. observa- 

 tion that there may be four or five. I have not had convenient 

 opportunity for tracing out this point myself in this country ; 

 but from specimens and observations sent, the attack is ob- 

 viously one that needs watching against and careful keeping 

 in check. 



Prevention and Eemedy. — One important measure is (as 

 in the case of the Elm-bark Scolytus) to remove all centres of 



* From original drawing, p. 2, of Mr. Chittenden's paper previously 

 referred to. 



