Miscellaneous. 241 



larvae of workers (which are barren females) and converting them into 

 queens by feeding them with peculiar food, used only for such as are 

 destined for sovereignty, and as the working ants are also barren 

 females, — is it probable that the ants have the power by selecting 

 one of their number to convert her into o, fertile female by the means 

 of some peculiar treatment which may cause the more full develop- 

 ment of those organs essential for impregnation ? I am aware in the 

 case of the bees this is accomplished in infancy ; still, as the matured 

 workers have t\iQ female organs perfect, though in a comparatively 

 low state of development, is it irrational to suppose, that when circum- 

 stances make it necessary, even at a later period of life, these same 

 all-important parts may be stimulated and rendered fit for the ac- 

 complishment of so desirable an object as reproduction ? I am also 

 aware that working ants, like working bees and wasps, do occasionally 

 lay eggs ; but when this does take place, they invariably produce 

 males, which I suspected could not be the case with those alluded to, 

 from the great disparity of size observable in the larvae and cocoons, 

 and which I should have been able to ascertain with certainty had 

 not the before-mentioned accident befallen them. 



I remain, dear Sir, yours respectfully. 

 To Richard Taylor, Esq. Henry Denny, A.L.S. 



On the Digestive Apparatus of the Gnat, Culex pipiens, Linn, 

 By F. PoucHET. 



The digestive apparatus of the Gnat is highly complicated : the 

 mouth is composed of two mandibles furnished with a row of stiff 

 fixed hairs, and of two maxillae bearing moveable cilia like the blades 

 of a fan and destined to collect the alimentary granules. 



The intestinal tube is remarkable from the presence of eight iso- 

 lated vesiculiform stomachs which are ovoid, thin, arranged symmetri- 

 cally around the intestine, and each communicating with it by means 

 of a short canal situated at the union of the anterior third with the 

 two posterior thirds of its internal region. These eight cavities 

 represent so many stomachs, and cannot be compared with the respi- 

 ratory vesicles described by Treviranus, Ramdohr, Cams, Meckel, 

 Owen, Newport and Lacordaire, in several insects belonging to the 

 order Diptera or Lepidoptera. At first sight these gastric cavities 

 are observed to be more or less filled with nutritious matter similar 

 to that perceptible in the remainder of the intestinal tube. These 

 vesicles in fact are seen to contract from time to time and successively, 

 in order to allow the alimentary substance to pass into the intestines. 

 The contractions are repeated at intervals of from twenty-five to 

 thirty seconds ; moreover on immersing these insects in liquids 

 coloured with carmine or indigo, the eight stomachs are observed in 

 the course of half an hour or sometimes less to be perfectly filled 

 with these substances ; the nature of these organs is consequently 

 beyond doubt. 



Although certain observers, as Swammerdam and Leon Dufour, 

 have asserted that several insects ruminate, it cannot be admitted 



Ann. ^ Mag. N. Hist. Ser. 2. Vol.i. 16 



