ScoLYTiD^. INSECTS. Loj<gicokma. 231 
districts of Germany, not supplied with coal like similar 
districts in our own country, but dependent for fuel on 
the forests of fir-trees, a species of Hylurgus began to 
increase, about the year 1780, to such an extent as to 
destroy in a few years whole forests. The working of 
the mines was in this way materially affected, as the 
proprietors had no fuel to carry on their operations. 
Those who wish to see the importance attached to the 
study of insects, destructive or otherwise to forests on 
the continent, should consult the handsome quarto 
volumes of Dr. Ratzeburg,* amply illustrated with 
figures. 
The larvae of this family of beetles, immediately after 
being hatched, excavate in the inner hark — as shown 
in the cut (fig. 127) copied from Ratzeburg — and 
partly also in the sapwood, “ lateral parallel channels 
more or less sinuous, proceeding on each side from 
a central one— that in which the eggs were placed — 
and thus giving to the under side of the detached bark 
and exposed sapwood that pinnated labyrinthine appear- 
Fig. 127. 
Excavated bark. 
ance and fancied resemblance to letters, which made 
Linnaeus affix to one of these insects the name of Typo- 
graphus." The effect of their ravages is to interrupt 
the course of the descending sap, and admit wet be- 
tween the bark and the wood, so that decay of the 
tree quickly ensues. The Hylesinus fraxini attacks 
the ash, and the Scolytus pygmmus the oak. The 
latter small beetle killed forty thousand trees in the 
Bois de Vincennes, near Paris. 
Entomologists have differed much in opinion whether 
the Scolytidae and Bostrichidae really injure and 
destroy trees in their growing state, or whether they 
only attack such as are already diseased. Captain 
Cox of Canterbury has published papers on the ravages 
of the Scolytidae, and suggested the means of arresting 
their progress. Mr. Alfred Wallace, who took very 
many species of them in New Guinea and other islands 
• Die Forst-insekten. 
of the Eastern seas, came to the conclusion that they 
only attacked dead wood, generally in the first stage of 
drying or decay.* In the course of five years almost 
daily spent in the forests, he never saw a single indi- 
vidual of either of these families attacking healthy living 
trees, nor did he find any traces of their having bored 
into such trees. Whenever a tree falls or is cut down 
these bettles are the first to attack it. In a few days 
dozens of small holes may be seen on the trunks and 
branches, from each of which a little fine wood-dust 
falls down; and on careful examination some of the 
insects may be seen pushing out the dust with the 
truncated end of the elytra. He mentions that he had 
cut dowm a large tree in the Aru islands of a kind 
which contained much milky sap, hardening into a 
kind of gutta percha on exposure to the air. Upon 
this tree he found many specimens of Scolytidae with 
their abdomens protruding from the holes they had 
bored, but all dead. They were glued fast by the 
hardening of the milky sap. The tree could not have 
been the proper food of this species, or the right place 
to deposit its eggs. In a hut in Macassar, formed of 
bamboos and palm, the Scolyti abounded. Mr. Wal- 
lace heard their never-ceasing jaws in the stillness 
of the night as they were at work. Mr. Waterhouse 
gives the names of thirty-nine species as British. 
They are in ten genera, the names of which are — 
Hylastes, Hijlurgus, Hylesinus, Phlwoph thorns, Scoly- 
tus, Xyloterus, Hypothenemus, Cryphalus, Tomicus, 
and Platypus. Most of the names are indicative of 
their gnawing into wood or bark. 
Group — LONGICORNIA {Longicorn Beetles). 
A very extensive and important section of Beetles, 
most of which are at once marked by the great length 
of the antennoe. How curious it is to see, as I have 
seen, a live specimen of the great Harlequin beetle of 
South America {Acrocinus lomjirnanus), with its coat 
of many pleasing colours, and its immensely long fore 
legs and long, long, antennae, crawl up a branch ! 
It places an antenna on the spot where it is about to 
plant its foot, doing this regularly one after the other. 
Many are the uses served by these antennae, and in 
this tribe they are remarkably varied. Look at the 
curious serrated edge of the joints in Westwood’s genus 
Scolecobrotus, certainly used by that Australian insect 
in some particular way; then look at the beautifully 
pectinated antennae of Polyarthron, Phcenicocerus, 
Petalodes, and other genera. See the short hetero- 
merous-like antennae of Spondylis and of some of the 
Brenthidm. The eyes are, in most, notched or kidney- 
shaped. But space forbids me entering into particu- 
lars about this really magnificent tribe, which varies 
in size from the minute Decarthria to the gigantic 
Titanus, or that immense AVest African Prionus de- 
scribed by Hope, or the beautiful large Batocera 
discovered by Mr. Wallace in one of the Eastern 
islands. For delicate colour, what can be sweeter than 
the curiously horned-headed Pheebe concinna (Plate 3, 
fig. 7), with its purplish lavender hues, and the pleas- 
ing variety of pale tints which set otf these purplish 
* Trans. Ent. Soc. London, new series, vol. v. p. 218 ; 1860 
