183 



November 24, 1835. 



Richard Owen, Esq., in the Chair. 



Mr. Yarrell exhibited a specimen of the Syngnathus Acus, Linn., 

 •with the view of again caUing the attention of the Society to the 

 fact that the males in this species of Pipe-fish are furnished with a 

 pouch under the tail, in which they bear about with them the ova 

 until the young have escaped from the capsule ; and which probably 

 serves also as a place of shelter to which the young can, for some 

 time after their exclusion, retreat in case of danger. In this indivi- 

 dual the opened abdomen exhibited the preparatory organs of the 

 male ; and the displayed subcaudal pouch showed many eggs con- 

 tained in it, the young of which were fully developed and ready to 

 escape from the capsules, while from others the young had actually 

 escaped. As a guide to those observers who may be desirous of 

 procuring specimens equally illustrative of the peculiarity of this 

 fish, Mr. Yarrell mentioned that the indi^adual exhibited was ob- 

 tained on the 20th of July. 



Mr.Yarrell read some "Notes on the Economy of an Insect destruc- 

 tive to Turnips"; which he prefaced' by adverting to the importance 

 to agriculture of an attentive collection of those entomological facts 

 which relate to species injurious to the ordinary crops of the farmer. 

 He then proceeded to remark that the turnip crop is in this country 

 usually infested in every season by two species of Haltica ; and that 

 another destroyer has been, in the dry summer of this year, super- 

 added to them, especially on the light and chalky soils. To the 

 history of this latter pest, which has been known to occur in those 

 seasons only in which there has been an almost total absence of rain, 

 Mr. Yarrell's paper is directed. A good account of a similar visita- 

 tion in 1782, as it was observed in Norfolk by Mr. William Marshall, 

 was published in the ' Philosophical Transactions ' for the following 

 year. 



Early in July last the " yellow fly " was seen upon the young tur- 

 nips. It was remembered by some farmers that this was the fly 

 which prevailed in the year 1818, and which was followed by the 

 caterpillars kno%\Ti by the name of the blacks. The eggs being depo- 

 sited by the perfect insect in the leaf of the plant, the black cater- 

 pillar or turnip-pest speedily makes its appearance, feeding on the 

 soft portions of the leaves of the turnips and leaving the fibres un- 

 touched ; and finally, casting its black skin and assuming one of a 

 more slaty or grey colour, it buries itself in the earth. Lodged there, 

 it forms for itself, from the soil, a strong oval cocoon ; from which 

 some of the earlier broods pass almost immediately into the perfect 

 state, filled with ova, and ready quickly to supply another generation 



