196 FEUIT INSECTS 



tallic greenish-blue, shining hke burnished copper when the 

 insect is flying. The males are smaller than the females and 

 have shining green heads. These sun-loving beetles begin to 

 appear early in May and continue through July even into 

 September. The females deposit their yellow, irregularly 

 ribbed eggs, about -V ^^ ^^^ "^^h in length, in cracks or 

 under bark scales, usually several eggs in a place, either on 

 the trunk or branches, and almost always on the warmer south- 

 ern side of the tree, or on recently felled logs in sunny locations. 

 The larva or grub which hatches from these eggs soon eats its 



way through the bark and ex- 



^ cavates a broad, flat, irregular 



^^ channel, often extending into the 



^^^m^ -^m sapwood just under the bark. 



■HHkjI^^^^^P^ Part of the channel is packed 



^^^^^^^^^^ with sawdust-like castings of the 



grubs. 



Fig. 187. — Flat-headed apple-tree a • i i c^ 



borer (X 1-). ^ Single borer maj^ often 



girdle the trunk and kill small 

 trees. The full-gTo^\^l, light-yellow, legless grub is about an 

 inch long with its second thoracic segment much broadened and 

 flattened (Fig. 187). On the upper and lower surfaces of this 

 segment are large, roughened spots with two smooth diverging 

 linear depressions extending through the dorsal spot and one 

 medially through the ventral spot. The grub habitually rests 

 in a curved position and gets its full growth during a single 

 summer. It finally extends its burrow outward nearly through 

 the bark, then digs a Httle deeper into the soUd wood, forming 

 a chamber in which it transforms through the tender white 

 pupal stage (Fig. 188) to the adult insect. In the north these 

 pupal chambers are made in the spring, the winter months 

 being passed as grubs, but farther south pupation may occur 

 in November, the pupae hibernating. The pupal period lasts 

 about three weeks in the spring, and the beetles cut their way 



