290 HABITATIONS OF INSECTS. 



is accidental or common to several of the tribe, but each peculiar to the 

 galls formed by a single and distinct species of Cynics. 



The Poma Sodomitica, mala insana, or apples of the Dead Sea, 

 beautiful to the eye, but filling the mouth with bitter ashes if tasted, 

 whose existence, though mentioned by Tacitus, Strabo, and Josephus, 

 has been questioned by Riland, Maundrell, and Shaw, and respecting 

 which numerous contradictory and erroneous opinions by more recent 

 authors have been collected by Mr. Conder in his Modern Traveller, have 

 at length had their true history developed by the late venerable vice- 

 president of the Linnaean Society, A. B. Lambert, Esq.^, Walter Elliot, 

 Esq., and J. O. Westwood, Esq.^ From their combined observations, it 

 has been ascertained that the Poma Sodomitica are actual galls, two 

 inches long and an inch and a half in diameter, of a beautiful rich glossy 

 purplish red exteriorly, and filled with an intensely bitter, porous, and 

 easily pulverized substance, surrounding the insect (^Cynips insana West- 

 wood), which has given birth to them, and were found by Mr. Elliott 

 growing on various species of dwarf oaks beyond the Jordan and in the 

 Troad, to the twigs of which Mr. Westwood remarks they are attached 

 in a curious manner, unlike what he has seen in any other galls, the 

 narrow end " rising upwards on each side and bending inwards, so as to 

 clasp the extremity of the twig somewhat like a pair of wide and curved 

 nippers." 



How the mere insertion of an egg into the substance of a leaf or twig, 

 even if accompanied, as some imagine, by a peculiar fluid, should cause 

 the growth of such singular protuberances around it, philosophers are as 

 little able to explain, as why the insertion of a particle of variolous matter 

 into a child's arm should cover it with pustules of small pox. In both 

 cases the effects seem to proceed from some action of the foreign sub- 

 stance upon the secreting vessels of the animal or vegetable : but of the 

 nature of this action wc know nothing. Thus much is ascertained by the 

 observations of Reaumur and Malpighi — that the production of the gall, 

 which, however large, attains its full size in a day or two^, is caused by 

 the egg or some accompanying fluid ; not by the larva, which does not 

 appear until the gall is fully formed^ : that the galls which spring from 

 leaves almost constantly take their origin from nerves'^; and that the egg, 

 at the same time that it causes the growth of the gall, itself derives nourish- 

 ment from the substance that surrounds it, becoming considerably larger 

 before it is hatched than it was when first deposited.^ When chemically 

 analyzed, galls are found to contain only the same principles as the plant 

 from which they spring, but in a more concentrated state. 



No productions of nature seem to have puzzled the ancient philosophers 

 more than galls. Theconnnentator on Dioscorides, Mathiolus, who agree- 

 ably to the doctrine of those days ascribed their origin to spontaneous 

 generation, gravely informs us that weighty prognostications as to the 

 events of the ensuing year may be deduced from ascertaining whether 

 they contain spiders, worms, or flics. Other philosophers, who knew 

 that, except by rare accident, no other animals are to be found in galls 

 besides grubs of different kinds, which they rationally conceived to spring 



> Linn. Trans, xvii. 445. « Trans. Ent. Soc. Land. ii. 16. 



3 Eeaum. iii. 474. * Ibid. 479. » Ibid. 501. « Ibid. 479. 



