396 DR. J. B. HICKS ON THE ORGANS 



melts away ; so that by the time the sac is in the proper focus, the appearance of the otolithe 

 has vanished ; and on further examination it will be plainly seen, especially where the 

 sac is viewed obliquely, that the appearance of a solid body was an optical deception, pro- 

 duced by the lookmg perpendicularly at the tube which passes from the sac beliind the 

 tympanum to communicate with the interior of the antenna : as the tube is seldom in the 

 centre, the appearance of the " otolithe " is usually more or less on one side. Another 

 great proof against the existence of an otolithe is the fact, that when looked at sideways 

 the sac is, so far as I can see, perfectly empty. 



M. Lesp6s, with myself, considers these organs to be none other than auditoi-y ; and 

 from the numerous researches which have now been instituted by Ei-ichson, Lespes, and 

 myself, I think we may safely say that their existence is very general if not universal 

 throughout the insect tribes. 



M. Lespes has also pointed out the peculiar hairs which I had noticed some time 

 since, and which I have figured in the Plate as they exist on the antenna of Dyticus 

 marginalis. 



Note. — The bleaching process which I now adopt is a slight modification of that formerly 

 recommended. I take chlorate of potash, say one drachm ; water one drachm and a half ; 

 mix these in a small bottle with a wide mouth, holding about an ounce ; wait five minutes, 

 and then add about 1^ drachm of strong hydrochloric acid : chlorine is thus slowly de- 

 veloped ; and the mixture remains in action from one to two weeks. 



EXPLANATION OP THE PLATE. 

 Tab. LXVII. 



A. Organs on the antenna of Microphora Vespillo. 

 Fig. 1. Enlarged view of the organs, between the hairs. Diameter yjoy of an inch. 

 Fig. 2. Section of antenna wall, showing the sacs behind the membrane. 



B. Organs on the antenna of Silpha ?. 



Fig. 1 . Enlarged view of organs, as seen from above, on the terminal joint : a a. large sort ; b b. smaller 



organs. 

 Fig. 2. Section of larger organs. Diameter at surface -yj-^q of an inch. 



C. Organs on the terminal joint of a Creophilus. 



Fig. 1. Shows the lozenge- shaped groups. 



a a. Organs from 6 to 16 in each group, divided by rows of hairs. Diameter j^'^^j of an inch. 

 b b. Large organs. 



i 



