100 TRANSACTIONS OF THE ILLINOIS 



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remaining segments are much narrower. The other form does not have 

 the first segment unusually enlarged, the whole body being somewhat 

 slender and tapering posteriorly, and each of the first three segments 

 with a pair small legs set wide apart. These larv^ are true wood- 

 borers, yet, as a rule, they appear to attack in preference those trees 

 which are suffering from some disease or impaired vitality, but yet not in 

 absolute decay. Still they do not appear to be confined to these, but are 

 often found boring into those which are apparently perfectly sound ; some 

 species also bore into the canes of raspberry bushes, etc. 



Chrysobothris femorata. Fabr. The Flat-headed Apple-treee Borer. 



This species is of a dark, dull greenish or dark grayish color, with a 

 strong coppery lustre ; the whole upper surface having the appearance of 

 being sprinkled with ash-colored powder ; the underside and legs of a 

 brilliant coppery color ; the feet green. The head is immersed in the 

 thorax to the eyes. The size varies considerably, but the length is usually 

 about half an inch. 



The larva is usually about seven-tenths of an inch long when full 

 grown ; soft, flesh-like, and of a pale-yellow color. The head is small 

 and deeply immersed in the following segment ; the jaws are black. The 

 second segment is very broad and large, being nearly twice the width of 

 any of the posterior segments ; it is rather broader than long, having on 

 the upper side a large oval, callous-like elevation, covered with numerous 

 brown raised points. 



The eggs are pale yellow, and irregularly ribbed or corrugated, 

 ovoidal, with one end somewhat flattened, and about one-fiftieth of an 

 inch long ; they are usually glued by the female under the loose scales or 

 in the cracks and crevices of the bark, either scattered singly, or, as is 

 often the case, several of them together. The young larvae hatched from 

 these gnaw their way through the bark, and gradually, as they grow, extend 

 their broad and flattened channels next the bark, girdling the smaller trees; 

 at length, when the larva has grown stronger and its jaws firmer, it bores into 

 the more solid wood, working upward until about to undergo its transfor- 

 mations, when it cuts a passage to the outside, leaving a thin covering at 

 the surface, through which the beetle afterwards forces its way. The 

 beetle usually makes its appearance in May or June. 



It is subject to the attacks of several parasites, some of which, though 

 not specifically determined, belong to Chalcididce, an extensive family of 

 small four-winged wasp-like flies, which probably deposit their eggs in the 

 larvae, and from which small white grubs, about the tenth of an inch long, 

 are produced, which finally destroy the borer infested by them. Prof. 

 Riley mentions two other parasites belonging to the Ichneumon family, 

 also wasp-like insects; one, which he names Bracon chariis, is about one- 

 third of an inch long, exclusive of the ovipositor which is a little longer 

 than the body; the abdomen, the rest black, the wings being a deep 

 smoky color, with a faint zigzag clear line across the middle from the 

 stigma. The other species is the Cryptus grallator oi Say, in which the 



