220 MISC. PUBLICATION 657, U. S. DEPT. OF AGRICULTURE 
and also larch and spruce. The larvae of Helops sp. occur beneath 
the bark of both decaying hardwoods and softwoods, as well as in the 
soil, and have been found in packing about plants intercepted at ports 
of entry. 
In addition to the wood-inhabiting forms just mentioned, beetles 
of the genera Hoplocephala (Arrhenoplita), Bolitotherus, and a few 
others infest various kinds of fungi attached to decaying wood. The 
males of both of the genera named have hornlike protuber ances com- 
ing from their bodies. Adults of the former are small, elongate, oval, 
and greenish in color; those of the latter genus are larger, being nearly 
14 inch long and having brownish, eylindr ical, warty pr otuberances on 
their bodies. Hoplocephala prefers a soft, light. papery, shelflike 
fungus, whereas Bolitotherus mntests a brown, woody Polyporus tun- 
gus in which to complete its development. 
Famiry LAGRITDAE 
Arthromacra aenea (Say) is a common beetle, 9 to 13 mm. in length, 
of a metallic blue, green or bronzy color, collected on shrubby foliage 
along woods roads. The larvae feed in decaying leafmold and are 
easily recognized by the clavate second joint of the antenna and the 
biconical spine on the tip of the ninth abdominal segment. The body 
is cylindrical and horny, and in other characters the larvae resemble 
the tenebrionids. 
Famity LYMEXYLIDAE 
The Ship-Timber Beetles 
The larvae of the ship-timber beetles are wood borers. The beetles 
are elongate and slender, with serrate antennae and large, four-jointed 
maxillary palpi. The head is deflexed, the eyes are large, the thorax is 
margined, and the elytra entire. The legs are slender and have five- 
jointed tarsi. The larvae are elongate, cylindrical forms, having the 
abdominal and thoracic seoments provided with minute chitinous 
asperities. The ninth abdominal segment is conspicuously armed, and 
the tenth is ventral, not terminal. The legs are five-jointed and well 
developed. The head is globular with a well-developed hypopharyn- 
geal bracon and chitinization of the hypopharynx. The clypeus and 
labrum are present, and the maxillary mala bears a terminal groove, 
indicating a division into lacinia and galea. 
The species of Melittomma have the ninth segment of the larvae 
truncate, rimmed with serrate teeth. They feed in chestnut. Hy- 
lecoetus spp. have the ninth larval segment ending in a long spur, and 
they feed in poplar, birch, maple, and other hardwoods. 
The chestnut timber worm (Jelittomma sericewm (Harr.)) is an 
elongate, subcylindrical, brown Noe, 11 to 15 mm. in length, clothed 
with fine silky pubescence. The beetles fly about the time the chest- 
nut isin bloom. The adult is nocturnal and rarely seen, but the larva 
(fig. 47, A, B, C) and its work are very common where chestnut still 
exists. Formerly this was a very important destructive insect, causing 
worm holes in 50 to 90 percent of the chestnut trees, thus unfitting 
the wood for many purposes. The eggs are laid in season checks on the 
surface of the wood where it is exposed through wounds or fire scars. 
It occasionally attacks white oak. The larvae bore deep into the wood, 
