758 



C E C I D O M Y I A. 



wheat that this insect, the Cecidomyia fritici 

 (Tipnla fritici, Kirby) makes its appearance, and in- 

 troduces its long retractile ovipositor into the centre 

 of the corolla, for the purpose of depositing its eggs, 



a, C. destructor, b, C. tritici. c, Larvae of ditto, feeding ; 



all magnified. 



the larvae produced from which, " perhaps by eating 

 the pollen, prevent the impregnation of the grain, 

 and so, in some seasons, destroy the twentieth part 

 of the crop." Mr. Shireff has also published an in- 

 teresting account of the proceedings of these insects 

 in the Magazine of Natural History for November 

 1829, stating, that they were first observed (at East 

 Lothian) on the evening of the 21st of June ; and, 

 " from the vast numbers seen, it is probable a few of 

 them may have been in existence some days previous. 

 The eggs were visible on the 23rd, the larvae on the 

 30th of that month, and the pupae on the 29th of 

 July. The flics were observed depositing their eggs 

 on the 28th, and finally disappeared on the 30th 

 July ; thus having existed throughout a period of 

 thirty-nine days. The flies almost invariably pre- 

 ferred the ears emerging from the vagina to those 

 farther advanced for depositing their eggs on, and as 

 one side only of the ear is exposed when the plant is 

 in this stage of growth, the other side generally re- 

 mained uniiijured. The fly deserted the fields as 

 the crop advanced towards maturity, and were found 

 longest in the spring-sown portion of the crop. It 

 seemed to feed upon the gum adhering to the newly- 

 emerged ears ; and as there is a great diversity 

 in the time of sowing wheat in this neighbourhood, 

 and consequently of the ears escaping from the 

 vagina, 1 attribute the unusual length of time it has 

 existed this season to the supply of food thus gra- 

 dually furnished." 



Both these insects are providentially kept in due 

 bounds by several species of parasitic flies belonging 

 to the families Ckalcididce and Proctotrupidce, the 

 proceedings of which, in destroying the Cccidomyice, 

 have been also recorded by the authors quoted above. 



In these two species of Cecidomyia, it is to be 

 observed, that, notwithstanding the differences in 

 their habits, it is only in the larva state that the 

 injury is produced ; but in other species of the genus 

 (Cecidomyia jriri, salicina, &c.), the females, at the 

 period of oviposition, introduce into the plant with 

 their eggs an irritating fluid, which causes the forma- 

 tion of a kind of gall upon the stems. De Geer has 

 given the history of these two insects, the latter of 

 which is found upon a species of willow at the end of 

 April, in the interior of a curious gall, resembling a 

 small double rose of a green colour, occupying the 

 extremity of one of the twigs, in the midst of which 

 is a small conical . cell formed of small leaves, in 

 which a single larva of a yellowish red colour, 

 without feet, is found, the body of which is corn- 

 posed of twelve rings, and is a little narrowed at its 

 anterior part, with the head rounded. On the Jlth 

 of the following month of May, in the same galls, 



DC Geer found a small white and very delicate 

 cocoon, which inclosed, without entirely concealing, 

 a small red pupa with white legs, and a bright red- 

 coloured abdomen, having a darker central line. 

 Having inclosed some of these galls in a box, several 

 small tipulideous insects made their way out of them, 

 which various authors, and 1 more especially M. Mac- 

 quart, whose recent work upon the Diptera forms a 

 valuable manual upon this order of flies, have also 

 observed subsequent to De Geer, and which they 

 regard as the Cecidomyia salicina. 



De Geer also describes the habits of three other 

 tipulidans, nearly allied to the preceding, namely, 

 the Tipnla junipcri (Linnaeus), which M. Meigen 

 places doubtingly in the genus Lasioptcra, and the 

 TipuI<B 9 pin and loti, which have been considered 

 both by Latreille and Meigen as Cecidomyiee, The 

 galls of the juniper are composed of six leaves, three 

 external, and three internal and smaller ; and De 

 Geer has observed, that, as the leaves of this plant 

 are always placed three by three, it would seem that 

 the gall is produced by the germ itself of three 

 smaller leaves, which, without this attack, would have 

 developed themselves, and ultimately produced a 

 new shoot. The larvae of the CecidomyicE feed upon 

 the internal leaves, the external ones then growing to 

 an unnatural size. In Sweden, the country people 

 employ these galls as a remedy for the whooping 

 cough, terming them kik-bar, which means berries 

 for the whooping cough, boiling them in milk. 



M. Macquart has also obtained the Cccidomi/ia 

 salicina from galls very similar to those described by 

 De Geer, which were found upon the Salijr alhti. 

 He has also observed upon the leaves of Artemisia 

 abrotanum the larva of a Cecidomyia, which feeds upon 

 the ground leaves of this plant without producing any 

 alteration or gall-like excrescence, and without in- 

 closing itself in a cell ; it, however, forms a very long 

 cocoon, in which it becomes a pupa. 



The small globular cottony balls which are often 

 to be noticed upon the Veronica chamcedrys, Tliymua 

 serpy/l/im, and Glechmna hederacea (ground ivy), are 

 also caused by the attacks of these minute flies. 



The author of this article has observed the proceed- 

 ings, and reared a large British species, whose habits 

 are very different from those recorded above, residing 

 in company, in large solid galls, the substance of which 

 is even firmer than the wood of the willow trees upon 

 which they are found. These galls are evidently the 

 result of the attacks of the parent fly depositing 

 several eggs on the same spot. We observed, also, 

 that this species is kept in check by not fewer than 

 five or six distinct species of still smaller parasites ; 

 and it appeared quite inexplicable to us how these 

 minute and feeble insects, unprovided as they are 

 either with instruments for burrowing or for eating 

 their way out of these hard galls, were enabled to 

 effect their escape. 



Under the article ARISTOLOCHI^E will be found an 

 account of the mode of impregnation of the Aristolo- 

 ckia clcmatitis, observed by Professor Willdenow by 

 means of the Tipula pennicornis, a species belonging 

 to* the present genus. A writer, however, in the 

 Annual Medical Review, quoted by Messrs. Kirby 

 and Spence, doubts the accuracy of this fact, on the 

 ground, that he could never find the Tipula, although 

 the plant produced fruit two years successively at 

 Brompton. We have observed, however, another 

 species very plentiful in the vicinity of that village, 



