ON TUE PALATABILITY OF SOME BRITISH INSECTS. 809 



Fig. 55. A drawing of a section showing the position, structure, and nerve-supply of 



the opercular organ of EutrochateUa jjulclieUa. 

 Fig. 56. A portion of the epithelium of the hypobranchial gland of Alcadia 



hollandi. Highly' magnified. 

 Fig. 57. A left lateral tooth from the radula of EutrocJiatella 'pulchella. Highly 



magnified. 

 Fig. 58. Radular teeth of AJcailia Inilhaiili, highly magnified : a, median ; 6, c, d, 



first, second, and third admedians of the left side ; f, one of the marginals 



or uncini ; e, a lateral tooth of the right side showing the stalk, stk., the 



aliform internal plate, al.p., the articular excavation, ari., and the 



process, ext.jj. 

 Fig. 59. Three rows of teeth from the radula of LiicideUa aureola. In this and 



the following figures only the pro.ximal members of the marginals are 



indicated. 

 Fig. 60. Two rows of teeth from the radula of PaJceohelicina idte. 

 Fig. 61. Two rows of teeth from the radula of Orohophana pachystoma ponsonhyi. 

 Fig. 62. Two rows of teeth from the radula of Aphanoconia ffouldiana. 

 Fig. 63. Two rows of teeth from the radula oi Aphanoconia andamanica . 

 Fig. 64. Two rows of teeth from the radula of Aphanoconia merguiensis. 

 Fig. 65. Two rows of teeth from the radula oi Aphanoconia rogersii. 

 Fig. 66. Shell of Aphanoconia rogersii. 

 Fig. 67. Shell of the same species, showing the aperture. 

 Fig. 68. Shell of the same species, viewed from above. 

 Fig. 69. Operculum of Aphanoconia rogersii, viewed from the inner or ventral side. 



3G. On the Palatability of some British Insects, with Note.s 

 on the Significance of Mimetic Resemblances. By 

 R. I. PococK, F.R.S., F.L.S., F.Z.S., Superintendent 

 of the Society's Grardens and Curator of Mammals. 

 With Notes upon the Experiments. By P^f. E. B. 

 PouLTON, F.R.S., F.Z.S. 



[Received and Read May 9, 1911.] 



Introduction. 



At the request of Prof. E. B. Poulton, F.R.S., I undertook, in 

 the summer of 1909 and again in that of 1910*, to make a series 

 of experiments in the Zoological Gardens to test the palatability 

 of various species of British Insects. Much of the material was 

 sent to me by Dr. G. B. Longstaft' from Morthoe in Devonshire. 

 Some I received from Prof. Poulton himself or from friends of 

 his. A few species I added on my own account ; notably the 

 stick insects and the ants, of which we had an abundant supply 

 in the Insect House in the Gardens. Those that I supplied 

 I identified myself. The rest were in all cases named by the 

 senders. To the insects Dr. Long.staif added a number of slugs, 

 which were identified, I understand, by Mrs. Longstaff. 



Since the majority of the experiments were made with English 

 Insects, it is regrettable that English, or at all events Palsearctic 

 birds, were, for the most part, unavailable for the tests. There 

 were two reasons for this. In the first place, Palsearctic insecti- 

 vorous birds were not sti'ougl)' repi-esented in the Society's 



* Records of a few experiments made in 1911 have been incorporated in the text, 



