354 ANNUAL OP SCIENTIFIC DISCOVERY. 



crow quill, and from an inch and a quarter to an inch and a half 

 in length. It has a reddish head, is whitish below and brownish 

 black above ; on each side are two longitudinal, wavy white lines, and 

 another, straight, on the middle of the back. When ready to wind 

 up, they swing down from the cotton plant, and, without any choice, 

 take up indifferently with the nearest objects on which they may rest 

 during this process. Their chrysalis state continues about twelve days ; 

 the moths then appear and immediately go about depositing their eggs, 

 after which they die. This perfect state lasts only four or five days. 

 Such is the routine of their reproduction. 



When they appear early in the season there are usually three 

 broods; but some years they come so late that only a single new gen- 

 eration is seen. In either case, the last brood almost invariably per- 

 ishes throughout, being either killed instantly by the frost, or dying 

 from starvation, having eaten all the cotton before their transformations 

 take place. It follows, therefore, that these ravaging insects, as they 

 appear in the cotton fields of the South, do so at the loss of that por- 

 tion of their race, for they leave no progeny behind them. At the 

 same time this condition of things makes the matter the more deplora- 

 ble for the planter, for as a suddenly invading foe from foreign parts, 

 he is rendered wholly powerless in averting this regularly periodical 

 destruction of property. 



ORIGIN AND PRODUCTION OF GALL NUTS. 



The name Gall is given indistinctly to various excrescences which 

 supervene upon the members of the vegetable kingdom, in conse- 

 quence of attacks of insects. Among these morbid productions, 

 some contain immediate principles, which are not without value as 

 reactives and medicaments. Such, for example, is the gall nut (prop- 

 erly so called,) an article of commerce, which furnishes gallic acid 

 and a very pure tannin. In studying the different productions of the 

 same sort, authors heretofore have paid attention only to exterior 

 forms of galls, to the plants which bear, and the insects which cause 

 them. Their development and structure hitherto have been un- 

 known. Logic would require that, in this double study, the organiza- 

 tion of these tumors should first be examined, so as to follow with 

 greater facility the phases of their growth. M. de Lecaze Duthiers, 

 a French botanist, has recently published a memoir upon this subject. 



Galls are generally considered as purely cellular mosses, which M. 

 Duthiers shows to be a mistake, for they contain the principal ele- 

 ments and the principal tissues which enter into the composition of 

 plants. There are internal and external galls. The cause of exter- 

 nal galls is the deposit of a venomous liquor of special specific prop- 

 erties, a real poison secreted by the insect, which deposits it in the 

 plant at the same time with its egg. The form, the consistence, and 

 all the characters of the tumors, vary with the specific properties of 

 the virus which superinduces their appearance. The internal galls 

 seem to owe their appearance (as Reaumer has suggested) to a con- 



