24)6 NATUnAL ARRAXGEMEXT OF INSECTS. 



parallel, and is knoAvn to every one : it is effected by 

 means of a beautifully contrived spring placed between 

 the nusothorax and the body ; — and the spines on the 

 posterior angles of the thorax have, no doubt, some 

 connection with this faculty. The larvse of these two 

 groups feed upon the roots or stems of trees, and the 

 perfect insects on the leaves and flowers of plants. 

 More than one species 'of Elater is highly luminous, 

 — the phosphoric light being emitted from a small 

 whitish oval spot placed on each side of the thorax. 

 Mr. Curtis has given a very interesting account of one 

 of these species, which our mutual friend, Mr. Lees, 

 brought home alive from the Bermuda Islands. Some 

 smaller groups of minute insects enter, also, within 

 this circle, but which we have no space to particularise. 

 (220.) The first, or more typical, family of this 

 group presents us with the remarkable feature of mo- 

 difications of form coincident with a certain geogra- 

 phical position ; but which we can scarcely attribute to 

 climatic influence exclusively — occurring as they do, in 

 the same belt. But they must be considered in con- 

 junction with local peculiarities and causes ; for East 

 and ^Vest, Zenith and Nadir, are convertible in their 

 application. We must not, however, be understood to 

 give an absolute restriction to the range of these forms, 

 for we sometimes find them crossing each other ; but 

 they then constitute the exception, and not the rule. 

 Thus, we have the obtuse, broad, flattened form of New 

 Holland instanced in Conoynatha ; the convex gibbous 

 form, narrowing behind, of India, found in Sternocera 

 Chrysis; — the African hairy lulodis; the attenuated 

 Indian form of Chrysochroa ; and the broadly dilated 

 Silpha-like shape of Madagascar Buprestidce. These 

 beautiful insects occur all over the known world, and 

 are eagerly sought by collectors, as elegant decorations 

 to their cabinets. They abound, particularly, in the 

 hottest climates ; and are excessively active during the 

 lieat of the season in which they occur, taking wing 

 promptly, and flying with great velocity and vigour. 



