80 CALIFORNIA STATE COMMISSION OF HORTICULTURE. 



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The worst representative of this family which we have in this State is 

 the peach-root borer {Sanninoidea opalescens). The following descrip- 

 tion of the different stages of this insect will aid those who are troubled 

 with this pest in detecting it: 



Egg. — The egg is very minute, not exceeding ^ mm. in length, oval, 

 light brown in color, and, when seen through a lens, ornamented with 

 hexagonal sculpturing. The eggs are deposited on the bark of the tree, 

 at or near the surface of the ground; rarely they are laid high up on 

 the trunk or even in the crotches of the trees. This last phase is gen- 

 erally found in the grafted trees, where gummy exudations have occurred 

 and where grafting has somewhat soured the sap. 



Larva. — The young larvae, on hatching, are very active and imme- 

 diately burrow into the tree, generally entering the cracks in the bark 



Female 



Male. 



Pupa. 



FIG. 72. Peach-root borer (Sanninoidea npalescens). 



at or below the surface of the ground. Here they remain constantly 

 feeding on the bark, at first near the surface, surrounding themselves 

 with gum, or coagulated sap, and gradually enter the sapwood, enlarg- 

 ing their burrows as they increase in size. The full-grown larva is pale 

 yellow, about one inch long, tapering with a brown head. After attain- 

 ing its growth, the borer ascends in the burrow to or above the surface 

 of the ground, as the case may be, and begins to spin a cocoon. 



Cocoon. — This is made up of a silken web mixed with castings and 

 earth glued together, and is of a brown color, from 1^ to 1^ inches long. 



Pupa. — The pupa within the cocoon is shiny, light brown, with num- 

 erous spines on the abdomen. When about to emerge the pupa is 

 pushed out of the cocoon, and soon the adult moth emerges. 



Moth. — To the novice this insect would appear more like a blue wasp 

 than a moth. The female differs so much from the male that they 

 might be taken for two distinct species. The female has bluish-black, 

 opaque front wings, while the hind wings are transparent, like those of 

 a wasp; the margin of both wings has a bluish-black fringe; antennae, 

 head, thorax, and abdomen are very dark steel blue, almost black; wing 

 expanse, 14 inches. The male has fore wings nearly transparent, with 

 upper margin and tips black; hind wings are transparent, like those of 

 female; the body is bluish black; the abdomen is much narrower than 

 that of female and more elongated; legs are black, with yellow tufts on 

 femur and tibia; wing expanse, 1^ inches. 



