74 DR. HARRIS’S REPORT. April, 
above. The head is broad, the thorax short, transverse, and as 
broad as the elytra; the antenne are ten-jointed, the first joint being 
very long, and the four last projecting at the sides like the teeth of a 
comb. But the mandibles, or upper jaws, of great size, extending 
like the horns of cattle, or branched like those of the stag, form the 
most conspicuous character. ‘These insects fly abroad during the 
night, and frequently enter houses. They are vulgarly called horn- 
bugs, and are dreaded for their formidable aspect, but are perfectly 
harmless. The larve are common in all decaying trees, and are 
frequently found in the trunks of apple-trees. 
The preceding insects have five joints to all their feet. There 
are others which injure vegetation, and which have only four joints 
to the posterior pair of feet. 
In Tenebrio, the body is elongated, hard, flattened, and entirely 
covered above ; the antenne are moniliform, or composed of grains 
like the beads of a necklace, and gradually enlarge towards the tips; 
the thorax is square ; the elytra are not united at their junction ; and 
the legs are curved. The larva is long, slender, nearly cylindrical, 
very smooth, and of a pale rust or dirty yellow color. The first 
segment behind the head is larger than either of the others ; this, as 
well as each of the two following segments, is furnished beneath with 
one pair of legs ; the tail is acuminated, the tip in some species fur- 
nished with two minute vertical spines ; under the tail, at the junc- 
tion of the two last segments, is a membranous space in which is 
concealed a retractile fleshy tubercle, from which issue, when the 
animal walks, two horny movable parts which perform the office of 
legs. ‘The larva state continues during two or more years. The 
perfect insects are nocturnal, as the name indicates. 
Fenebrio granarius. ‘The larva lives in stables and granaries, 
subsisting upon corn and meal. It has considerable resemblance to 
that of the small species of Elater. The pupa is found in June in 
places inhabited by the larva. The perfect insect is developed about 
the middle of June. 
A remarkable case of the introduction of this insect into the hu- 
man body is recorded by the late Dr. Coffin of Boston, exhibiting 
a great change in the ordinary habits of the insect, showing the ne- 
cessity of great attention to cleanliness in cases of sicknéss, and fur- 
