COLEOPTERA. CURCULIONID^E. 351 



The perfect insects are of small size, and of obscure colours ; but 

 they are, nevertheless, amongst the most destructive of the insect 

 tribes : of these, the Scolytus destructor is the most obnoxious in this 

 country, annually destroying a great number of elm trees in the neigh- 

 bourhood of London ; and the injury is gradually spreading into the 

 provinces, owing to the inattention or ignorance of those whose duty 

 it is, or ought to be, to adopt decided measures for stopping the mis- 

 chief. The parks and public gardens and walks around London have 

 been especially subject to the attacks of these insects. It has, in- 

 deed, been a question whether the insects were the primary cause 

 of the mischief, or whether the trees were not previously infected 

 in some way or other, and thus rendered an agreeable nidus for the 

 insect. From the recent observations of Messrs. Audouin and Spence, 

 it, however, appears evident that, in the first instance, both the male 

 and female insects attack the trees for the purpose of obtaining food, 

 burrowing into the trunk. This brings the trees into a state of ill 

 health, which is adapted for the reception of the eggs and food of 

 the larva. The female insect then burrows deeper into the trunk, and 

 there deposits her eggs ; and the larvae {Jig- 42. 4.), when hatched, 

 form cylindrical galleries, diverging at right angles from the track of 

 the parent, and parallel to each other; within which they also become 

 pupae {fig. 42. 8.) ; and so great is the fecundity of these insects, 

 that their countless numbers are soon sufficient to destroy the largest 

 tree. I must refer the reader to papers upon this subject by iVIr. 

 MacLeay, in the Edinburgh Pkilosoph. Journ. July, 1824, p. 123. ; 

 Curtis, Brit. Ent. art. 43.; to numerous articles in the 1st, 2d, 

 and 3d vols, of the Gardeners Magazine ; the 18th number of the 

 Magazine of Nat. Hist. ; Tilloch's Phil. Mag. October, 1823. ; Times 



Brehm. Uber dcr Borkenkafer ; Isis, 1 829. 



Theirsch. Die Forstkafer, &c. 4to. Stiittgard, 1830. 



Gmelin. Abhandl. iiber die Wurmtrokniss. 8vo. Leipz. 1787. 3 col. pi. d. Ditto, 



Anhang. &c. (supplement to ditto), 8vo. Lcipz. 1787. 

 Hammer. Notice sur le Typographe, in Journ. Soc. Sc. Agric. &c. Bas Rliin. 



No. 3. 1826. 

 Panzer, in Der Naturforscher, 25 st. 1791. (Several minute Tomiei.) 

 Haas. Beobachtungen iiber den rindun oder Borkenkafer. Erlang. 8vo. 1793. 

 J. G. Bernstein. Antitypograplui.s, &c. 8vo. Leipz. 1793. 

 And tlie general works of Fabricim, Gi/lleiihaU, Paijkull, Jlcrhst, Kirhy, Stephens, Sec. 



