COLEOPTERA 529 



grown, a hole 12 mm. in diameter. The pupa state is passed within 

 the burrow. It sometimes occurs in such numbers as to kill the 

 infested trees. 



The rounded-headed apple-tree borer, Saperda Candida. — Except- 

 ing the codlin-moth, which infests the fruit, this is the worst enemy of 

 the apple that we have. Its common name is used to distinguish it from 

 the flat-headed apple-tree borer, already described, the larva of this 

 species being nearly cylindrical in form (Fig. 635). The eggs are laid 

 on the bark at the base of the tree late in June or July. The larva 

 at first bores in the soft sap-wood, making a disk-shaped mine; 

 after this it works in an upward direction 

 in the harder wood, and at the close of its 

 larval existence comes to the surface sev- 

 eral inches above the place it entered. 

 Itrequires nearly three years for this larva 

 to attain its growth ; it changes to a pupa, 

 near the upper end of its burrow, about 

 the middle of May, and emerges as a 

 beetle in June. The beetle (Fig. 644) is 

 of a pale brown color above, with two 

 broad white stripes extending the whole 

 length of the body. Although the larva Fig- 644- 



is found chiefly in apple, it infests many 



other trees. The presence of the borers can be detected by the saw- 

 dust-like castings which the larvee throw out at the entrances of their 

 burrows. 



The two-spotted oberea, Oberea bimaculdta, is sometimes a serious 

 pest, boring in the canes of blackberry and raspberry. The larva 



resembles that of the preceding 

 species. The adult (Fig. 645) is 

 about 12 mm. in length and of a 

 deep black color, except the protho- 

 rax, which is yellow. There are usu- 

 ally two or three black spots on the 

 pronotum, but frequently these are 



Fig. 645. Fig. 646. wanting. 



By cutting and burning all the 

 canes after the crop has been picked, the borers in them can be 

 destroyed. 



The red milkweed-beetles, Tetraopes. — There are several species 

 of bright red beetles that are common on milkweeds (Asclepias). 

 These belong to the genus Tetraopes. Our most common species 

 (Fig. 646) is T. tetraophthdlniMS . In this species there are four black 

 spots on each wing-cover, and the antennae are black and not ringed 

 with a lighter color. The larva bores in the roots and the lower parts 

 of the stems of milkweeds. 



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