150 DR. J. BRAXTON HICKS ON UNDESCRIBED SENSORY ORGANS IN INSECTS. 



wliicli impressions can be conveyed to tliem, can easily be seen in Diptera, Hymeno- 

 ptera, and Lepidoptera. 



The same must be said of those on the legs, which I have described above. If Ave 

 observe an Insect, that joint around which the organs are placed does not touch the 

 surface over which it is running, but remains at some distance above it : in this also the 

 air must be the medium of communication. 



The delicacy with which odours are perceived by many insects argues an olfactory 

 apparatus of considerable perfection ; and it seems to me not improbable that these latter- 

 named organs may be in some way connected with the sense of smeU, or perhaps with 

 some sense not to be found in the Vertebrata. 



In conclusion, I again ventiire to recommend the process of bleaching by chlorine, to 

 which I have already called attention in my former papers. It is easily managed, always 

 efficacious, and invaluable in researches of this nature, and equally adapted to decolorize 

 Crustacea, Arachnida, and Insecta. Without it, I should have been unable to arrive at 

 the results here detailed. 



DESCRIPTION OP THE PLATES. 

 Tab. XVIII. 



Fig. A. Halter of (Estriis Equi. 



1. Showing the groups of organs {ad) at base on one side; b b, nerves to them. 



2. Section of base : a a a, organs in section ; b b b, nerves proceeding to each group. 



3. Magnified view of the lateral groups: a, seen from above; b, seen in section. 



4. Magnified view of the lower group : a, seen from above ; b, seen in section. 



Fig. B. Under surface of nervure in elytron oi Aromia moschata : a a, vesicles ; b b, nerve proceeding to 



them. 

 Fig. C. Organs on legs oi Hvppobosca [a a a). 



1, OiH. Hirundinis. Diameter of each vesicle ttVit inch. 



2. Of H. Ovis. 



Fig. D. Organs on trochanter-femoral joint oi Musca domestica {a). Diameter of each -^-^^-^ inch. 

 Fig. E. Organs on trochanter of Silpha (1 a a). 



2. Enlarged view from above. Diameter of largest xaTu inch. 

 Fig. F. Organs on trochanter oi Lampyris noctiluca (Glow-worm). 



1. Under surface : a, organs; b, main nerve of leg; c, branches to organs. 



2. Upper surface. 

 Fig. G. Trochanter of Meloe. 



1. b b, organs in situ; a, nerves proceeding to each. 



2. Section of wall, showing the nerve («) passing to the papilla {b). 



3. Magnified view of organs and papillfe from above: a a, nerve ; b, papilla. 

 Fig. H. Trochanter-femoral joint of Forjicula auricularis (common Earwig). 



1. Under surface. | ^^^ ^ ^^.g^^^_ Diameter xtVo inch. 



2. Upper surface. J 



