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colored. The wings, four in number, are smoky-brown and 

 semi-transparent. The legs are ochre-yellow with blackish 

 thighs. 



When about to lay her eggs she draws her borer out of 

 its sheath till it stands perpendicularly under the middle of 

 the body; then she plunges it through the bark into the 

 wood. When the hole is made deep enough she then drops 

 an egg therein, conducting it by means of the two furrowed 

 pieces of the sheath. The borer often pierces the wood to 

 the depth of half an inch or more, and not unfrequently 

 becomes a victim to her own zeal and labor, driving in her 

 borer so tightly that she is unable to extract it and perishes 

 from starvation. 



The eggs are oblong and less than one-twentieth of an* 

 inch in length. The larva is a yellowish white, of a cylin- 

 drical shape, with a horny point on the upper part of the 

 hinder extremity. They feed exclusively on wood, making 

 long passages through it and destroying much valuable 

 timber. As they grow very slowly, and remain several 

 years in the larva state, they often become injurious to 

 whole forests of trees. 



The Tremex is considered one of the most destructive 

 insects in the eastern states. In the year 1873, I received 

 from Oregon, Illinois, a piece of Hickory bark with the 

 female attached, who, being unable to extract her borer, 

 had perished. They had destroyed many of the trees in 

 that part of the state. 



The larva is often destroyed by the maggots of two kinds 

 of Ichneumon flies, (Pimpla atraia and lunator^) Fabricius. 

 These flies thrust their slender borers, measuring from three 

 to four inches in length, into the trunks of trees inhabited 

 by the grubs of the Tremex, and their life is often lost by 

 being in like manner fastened to the trunks of the trees. 



The male of the Tremex Columba is very unlike the female 

 in color, form and size, and is not furnished with the 

 remarkable borer of the other sex. He is rust-colored, 

 variegated with black. His antennae are rust-colored or 



