1838. HOUSE— No. 72. 85 



land Farmer. Its perusal is earnestly recommended to all who take 

 an interest in the history of the contagious diseases of plants. 



The insects of this family have the body cylindrical or globose ; 

 the antennae with not more than ten distinct joints, terminated by a 

 thickened, solid, or perfoliate mass, composed of two or three joints ; 

 the joints of the tarsi or feet are not spongy beneath, and the anterior 

 legs are dentated or toothed. 



Their larvae are small, short, white grubs with horny heads, and 

 six small feet attached to the three anterior segm.ents. Their jaws 

 are very hard, and formed for cutting woody substances, which they 

 reduce to fine powder. They remain one or two years in the larva 

 state, and do not quit the trees which they inhabit until they have 

 become perfect insects. The places of their exit are perfectly cy- 

 lindrical holes. 



In HylurguSy the body is cylindrical and is obtuse behind ; the an- 

 tennae are short, composed often joints, the three last forming a round- 

 ed mass. The last joint but one of the feet is divided into two lobes. 



Hylurgus terebrans^ is a large insect, apparently capable of doing 

 much mischief. It is very common during the months of April, May 

 and June, on newly made board-fences, and on lumber wharves ; but 

 I have not been able to ascertain upon what tree it resides ; though 

 probably it inhabits some of the pines, hemlocks, or cedars employed 

 as lumber. 



Hylurgus dentatus is found in October, on the trunks and under 

 the bark of the red cedar. The bark of this tree is perforated by 

 thousands of small holes, from which have escaped these little beetles. 

 The female forms a cylindrical passage beneath the bark, where she 

 deposites her eggs. The larvae proceed from this path, in feeding, 

 at right angles, forming on each side numerous parallel furrows, small- 

 er than the central tube of the female. The larvae live between the 

 bark and the wood, and by their ravages loosen the former, and 

 arrest the formation of new wood. 



In the insects, referred by Prof. Peck to the genus Scolytus, the 

 body is short and cylindrical ; the thorax is arched so that the head is 

 situated beneath its anterior part ; the antennae are ten-jointed, the first 

 joint is long, and thickened at the end, the second cup-shaped, the third 

 to the seventh, inclusive, are minute, but gradually increase in size. 



