SCOLYTID^.- 



-INSECTS.- 



-LOXOICORXIA. 



231 



<lis(ricts of Germany, not supplied with coal like similar 

 districts in our own country, but dependent for fuel on 

 tlie forests of fir-trees, a species of Hijhtrgus 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 

 prsiprietors 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 larvie of this family of beetles, immediately after 

 being hatclied, excavate in the inner bark — 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- 



( ■■■">'^ ,.-■'■"■'. 7ri<*: 



K.\c;ivfttetl b;u k 



ance and fancied resemblance to letters, which maile 

 Linnajus 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 Ili/lesinw fraxini attacks 

 the ash, and tlie Scohjtus jiyrpnrvus the oak. Tlie 

 latter small beetle killed forty thousand trees in the 

 Bois de Vincennes, near Paris. 



Entomologists have differed much in opinion whether 

 tlie Scolytida; and Bostrichidse really injure and 

 destroy trees in their growing state, or whether they 

 only attack such as are already diseased. Captain 

 Cox of Canterburj' has published papers on the ravages 

 of the Scolyliche, 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-iusckten. 



of the Eastern seas, came to the conchision 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 bettlcs 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 wxod-dust 

 falls down ; and on careful examination some of the 

 insects may be seen pushing out the dust with tlie 

 truncated end of the elytra. He mentions that he liad 

 cut down a large tree in the Aru islands of a kind 

 which contained much milky sap, hardening into a 

 kind of gutta perclia on exposure to the air. Upon 

 this tree he found many specimens of Scolytidre with 

 their abdomens protruding from the holes they had 

 bored, but all dead. They were glued fiist 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, Hylurgiis, Hylesinus, Phleeophthorus, Scoly- 

 ttis, Xyloterus, Hypothenemus, Cryphalus, To)7ucus, 

 and Platypus. Most of the names are indicative of 

 their gnawing into wood or bark. 



Gi:<jl;i' — LONGICORNIA {Longicorn Beetles). 



A very extensive and important section of Beetles, 

 most of whicli are at once marked by the great length 

 of the antennre. How curious it is to see, as I have 

 seen, a live specimen of tlie great Harlequin beetle of 

 South America [Acrocinus lomjimanus), w-ith its coat 

 of many pleasing colours, and its immensely long fore 

 legs and long, long, antennre, crawl up a brancli ! 

 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 antennse, and in 

 this tribe they are remarkably varied. Look at the 

 curious serrated edge of the joints in AVestwood's genus 

 Scolecohrotus, certainly used by that Australian insect 

 in some particular way ; then look at the beautifully 

 pectinated antenna! of Polyarthron, Phcenicocerus, 

 Pdaloch'S, and other genera. See the short hetero- 

 merous-like antennre of Spondylis and of some of the 

 Brenthidiv. 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 

 Tltanii-s, or that immense West African Prinnus 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 Pkahe concinna (Plate 3, 

 fig. 7), with its purplish lavender hues, and the pleas- 

 ing variety of pale tints wliich set off these purplish 

 • Trans. Eut. Soc. Loniloii, new series, vol. v. p. 218 ; 18C0. 



