60 INSECTS OF MASSACHUSETTS. 



base of it in the females. The legs are short, the first pair being 

 the largest, and the hindmost unusually distant from the middle 

 pair. These insects live under the bark and in the trunks of 

 trees, but very little has been published respecting their habits ; 

 and the only description of their larvae that has hitherto appeared 

 is contained in my first Report on the Insects of Massachusetts, 

 printed in the year 1838, in the seventy-second number of the 

 Documents of the House of Representatives. 



The only beetle of this family known in the New England 

 States is the Brent hits (Arrhenodes) scptemlrionis* of Herbst, 

 the northern Brenthus, so named because most of the other spe- 

 cies are tropical insects. It is of a mahogany-brown color ; the 

 wing-cases are somewhat darker, ornamented with narrow tawny 

 yellow spots, and marked with deep furrows, the sides of which 

 are punctured ; the thorax is nearly egg-shaped, broadest behind 

 the middle, and highly polished. The common length of this 

 insect, including the snout, is six tenths of an inch ; but much 

 larger as well as smaller specimens frequently occur. The north- 

 ern Brenthus inhabits the white oak, on the trunks and under the 

 bark of which it may be found in June and July, having then 

 completed its transformations. The female, when about to lay 

 her eggs, punctures the bark with her slender snout, and drops an 

 egg in each hole thus made. The grub, as soon as it is hatched, 

 bores into the solid wood, forming a cylindrical passage, which it 

 keeps clear by pushing its castings out of the orifice of the hole, 

 as fast as they accumulate. These castings or chips are like very 

 fine saw-dust ; and the holes made by the insects are easily dis- 

 covered by the dust around them. When fully grown, the grub 

 measures rather more than an inch in length, and not quite one 

 tenth of an inch in thickness. It is nearly cylindrical, being only 

 a little flattened on the under-side, and is of a whitish color, ex- 

 cept the last segment, which is dark chestnut-brown. Each of 

 the first three segments is provided with a pair of legs, and there 

 is a fleshy prop-leg under the hinder extremity of the body. The 

 last segment is of a horny consistence, and is obliquely hollowed 



* A mistake undoubtedly for scptcmtrionalis. It is the Brenthus marillusus of 

 Olivier and tichonherr. 



