128 



INSECTS AFFECTING THE ORANGE. 



FIG 



Oncideres 



cingulatus. (After 

 Kiley.) 



THE TWIG GIRDLER. 



(Oncideres cingulatus, Say). 

 [Figs. 49 and 50.] 



This beetle is injurious to fruit and timber trees in all parts of the 

 southern and eastern United States. The female has the singular 

 habifc-of cutting off twigs and branches not exceeding three-fourths of 

 an inch in diameter in which she had previously depos 

 ited a number of eggs. Fig. 49 shows the insect in the 

 act of cutting a twig. In the South the Persimmon suf- 

 fers most severely, but Oak, Hickory, Cherry, in fact, all 

 hard-wood timber and fruit-trees, are attacked, and 

 even climbers and ligneous shrubs like the Eose are not 

 exempt. 



Coextensive depredations upon the Orange have hith- 

 erto been reported, but in most groves an occasional 

 branch is amputated. The loss is seldom noticed ex- 

 cept in young trees, which it is sometimes provoking to 

 find deprived of their leaders of the previous season's 

 growth. The cutting is so cleverly done as to pass for 

 a malicious use of the pruning shears, and few persons 

 would suspect it to be the work of an insect. 

 The beetle is about 16 mm (/ ^ - inch) long, rather stout and cylindrical, 

 dark chocolate-brown in color, speckled with lighter brown, and lightly 

 covered with short, gray pubescence, resembling a coat of bluish dust 

 or pruina, denser beneath and upon head and thorax, and forming a 

 broad transverse band upon the wing-cases. The antennae of the female 

 about equal the body in length, and are somewhat longer in the male. 

 There is but one brood each year. The eggs are laid in September and 

 October, and are deposited singly beneath the bark, usually close to a 

 bud. [Fig. 49, b; e, egg, natural size.] After placing an egg under each 

 bud for a distance of two or three feet, the female cuts off the branch 

 containing them by gnawing around it a deep, narrow groove, .so nearly 

 severing it from the tree that it falls by its own weight, or is broken 



off by the wind and falls to the ground, 

 where it obtains the moisture necessary to 

 the development of the young. The eggs 

 hatch into white, fleshy Iarva3 of the form 

 common to wood-boring beetles, and known 

 in the South as "Sawyers." (Fig. 50, a.) 

 The larvaB remain nearly a year feeding upon 

 the wood of the fallen branch, which they 

 riddle with their galleries, and in the latter 

 part of summer form within the wood oval cells, in which they trans- 

 form to pupa. .(Fig. 50, b.) 

 The perfect beetles appear again in September. They are very shy, 



FIG. 50. Oncideres cingulatus. a 

 larva ; b, pupa. (After Kiley.) 



