VOL. XX.] PHILOSOPHICAL TRANSACTIONS. 233 



Some Chinese Astronomical Observations. Communicated by M. James Cassini. 



N°237,p. 53. 



These are observations made at Pekin, by which M. Cassini determines the 

 latitude and longitude of that place, the former by observed altitudes of the 

 pole-star^ which corrected for refraction, &c. give 39° 55' 30' for the latitude 

 of Pekin ; and the latter by the observed eclipses of Jupiter's satellites, which 

 give, for its longitude, 7h. 354^ min. or 113° 52^' east of Paris. 



On the Origin of Caterpillars that infest Fruit Trees. By Dr. Geo. Garden, of 



Aberdeen. N° 237, p. 54. 



I had occasion some years ago to discover the true origin of the small cater- 

 pillar, which infests the blossoms of pears and apples, and destroys the fruit. 

 The vulgar conceit was, their being bred of mists and dews, which Goedartius 

 assents to, but Dr. Lister rightly conjectures their original to be from the 

 butterfly, into which they are transformed, though he seems not to have taken 

 notice of the particular manner of their propagation, as may be seen in his 

 edition of Goedartius. The bearers of these trees are full of asperities, and not 

 so smooth in their bark as the other parts of the tree. If, after the harvest, 

 and any time during winter, you look upon these bearers through an ordinary 

 microscope, you will find the cavities full of eggs of an oblong figure, and 

 citron colour, especially in those years and trees wherein the caterpillars have 

 been numerous ; out of these they are hatched in the spring. The seasons 

 which usually destroy them, are, when there comes an early heat, such as is 

 sufficient to hatch them before the coming forth of the buds and blossoms, and 

 when immediately there succeeds a nipping frosty air, which soon kills them. 



The discovery of this manner of their propagation, seems to give light to 

 these conjectures. 1 . That we ought not to conclude that any insects are bred 

 of corruption, and not exovo, because we cannot discern the particular manner 

 of their propagation ; for the discovery of this is by accident; and not discerni- 

 ble by the naked eye. 2. That the female insects of all kinds of flies, and 

 butterflies, probably put their spawn near those places where the erucas which 

 are hatched of them are to have their food, so that they are to be searched for 

 in such places. 3. They seem to be fixed into the cavities of the bearers by a 

 gluten, so as that rains do not wash them off". The greatest frosts, it seems, 

 do no hurt to the small eggs of insects ; for I have seen the caterpillars hatch, 

 after most cold and frosty winters, from those eggs which I have observed on 

 the bearers all the winter over. 



VOL. IV. Hh 



