Linnaan Society. 277 



that the extremity, which is free and usually round or somewhat 

 pointed, can be slightly elevated, depressed, extended, retracted and 

 moved laterally at will ; and mentions that Professor Owen has de- 

 tected a rudimental labrum in spiders of the genus Mygale. To 

 apply the term mandibles to organs originating above the labrum, 

 and therefore not situated within the mouth, is evidently erroneous ; 

 and the author ventures to anticipate, upon anatomical consider- 

 ations, that future investigations will lead to the conclusion that the 

 mandibles of the Araneidea are confluent with the palate. 



March 6, 1849.— R. Brown, Esq., V.P., in the Chair. 

 The necessary business of the Meeting having been disposed of, 

 the Vice-President in the Chair proposed, that, in consequence of 

 the recent death of Edward Forster, Esq., Treasurer and Vice-Pre- 

 sident of the Society, and in consideration of his long connexion 

 with, and eminent services to, the Society and to Natural History, 

 the Meeting should adjourn ; which was unanimously agreed to. 



March 20. — The Lord Bishop of Norwich, President, in the Chair. 



Read a paper ?? On the Anatomy and Development of certain Chal- 

 cididce and Ichneumonidce, compared with their special economy and 

 instincts ; with descriptions of a new genus and species of Bee Para- 

 site." Part I. By George Newport, Esq., F.R.S. & L.S. 



Mr. Newport remarked that the parasitic Hymenoptera in their 

 larva state are among the most imperfectly organized forms of 

 Articulata, and yet, having passed through this stage of their exist- 

 ence, they become some of the more active and perfect of insects. 

 They are nourished by suction, and either are attached singly to the 

 external surface of the bodies of their victims, or reside in the same 

 cells with them gregariously, or infest them internally, according to 

 their species. In the whole of them, however, the general form of 

 body and of the digestive organs, at the earlier periods of growth, is 

 very similar, and the special development of each species is regulated 

 by the same laws. They cast their tegument at different periods of 

 growth like other larvae, a fact which Mr. Newport has observed in 

 Paniscus, although in the apodal larva? of Hymenoptera it has 

 heretofore escaped the observation of naturalists. Their digestive 

 apparatus at first is extremely simple, and has the form of a capa- 

 cious bag or sac, without any anal outlet. Consequently no fasces 

 are passed until the larvae have acquired their full growth and ceased 

 to feed. After this period of assimilation the digestive cavity begins 

 to assume a new condition. It becomes perforated at its base, and 

 an intestine and anal outlet are formed, and faeces are then passed. 

 One reason for this late completion of the alimentary canal seems to 

 be the necessity that the fluids of the insect preyed upon should be 

 preserved in a healthy state for the support of the parasite ; and 

 another, that the food of the victim should not be contaminated. But 

 when the parasites are full-grown the necessity for these conditions 

 ceases, and the intestinal portion of the digestive apparatus is deve- 

 loped. 



