632 PHILOSOPHICAL TRANSACTIONS. [aNNO I74g. 



the dew; or any time of the day in rainy weather; for then they are not able 

 to fly. 



It has been already noticed, that, if the weather be cold or wet in autumn, 

 they generally hide themselves in secret places, where they lay their eggs, and 

 then die : hence great care should be taken at this time, when the ground is 

 freed of its crop, to destroy them, before they lay their eggs. 



In the month of September 1748, certain intelligence was received, that se- 

 veral swarms of locusts came out of Walachia into Transilvania, through the 

 usual inlets, and took possession of a tract of land in the neighbourhood of 

 Clausberg, near 3 miles in length ; where it was not possible to save the millet 

 and Turkish wheat from these devourers. 



The eggs of these animals, which have been preserved in dry mould, have pro- 

 duced nothing; but those that have been preserved in mould moistened with 

 water from time to time, gave early in the spring of 17 4g some of these gras- 

 hoppers. The little ones were, soon after they came forth, of the size nearly of 

 ordinary flies: They had already the form of grashoppers, but they had as yet 

 no wings. This observation shows, that the author of the foregoing account 

 was mistaken, when he says, " these insects had at first the form of grubs, or 

 small worms." They change their skin several times, but they do not acquire 

 wings till they have changed for the last time. 



The grashoppers taken in England in 1748, have been compared with those 

 that have been sent over from Hungary and from Poland that same year, and 

 they have been found to be perfectly of the same kind. There are in Sir Hans 

 Sloane's collection * some of the same sort of locusts or grashoppers, preserved 

 in spirits of wine, and which were taken up here above 30 years before, and are 

 exactly like those from Egypt and Barbary. 



Concerning some Vertebrce of Ammonitce, or Cornua Ammonis. Communicated 

 by Mr. Henry Baker, F.R.S. N° 491, p. 37. 



This curious fossil was sent to Mr. B. by Dr. Miles, of Tooting, f.r.s. It 

 consists of 26 joints, which he calls vertebrae, and supposes to have been the 

 joints of the back bone or tail of some animal ; but, on considering them with 

 attention, they will perhaps rather be judged to be the several articulated divi- 

 sions that compose the body of some kind of nautilus, or of some one of the 

 various species of the ammonitae : which opinion is supported, not only by the 

 spiral figure, which they form when put together, but also by the traces or 

 markings of such articulations, found on some particular kinds of fossil nautili 

 and ammonitae. 



All the parts of this uncommon fossil are converted into a kind of sparry sub- 



• See Sir Hans Sloane's Hist, of Jamaica, vol, I. p. 29. — Orig. 



