372 Miscellaneous. 



Conb-ibutions to the Knoiuledge of the Antennary Sense-Organs of 



Insects. By C. M, Child, of the Zoological Institute, Leipzig 



Universitj'. 



After being occupied for some months in studying the larvae and 

 pupae of Moclilonyx [Corethra'\ culicifonnis, Dog., and Corethra 

 j^himicornis, F., in the laboratory of Privy Councillor Leuckart, my 

 attention was directed to a singidar organ at the base of the antenna 

 in these insects. Upon further investigation it has been found that 

 the structure in question is a highly developed sense-organ, an 

 organ which, as I gradually learnt, is not only present in the 

 Nematocera, but is also of fairly frequent, if not of universal, occur- 

 rence in the most widely different orders of insects. 



The literature upon the subject I found to be verj- scanty, and 

 for the most part out of date and incomplete. On account of its 

 structure and position the organ was regarded by Johnston * as 

 having an auditory function. Mayer t performed certain experi- 

 ments with living gnats, which confirm rather than refute this view. 

 "Weismann J has studied the development of the organ, but leaves 

 the question as to its function entirely undecided. Hurst § gives a 

 very inexact and partly incorrect description of the structure of the 

 organ, and agrees with Johnston and Mayer in regarding it as 

 auditory. 



Moreover, as I convinced myself in the course of my investigations, 

 the organ in question is possessed not only by the gnats, but also 

 by all Diptera, so far as I have examined them. Tliis general 

 occurrence among the Diptera induced me to investigate other orders 

 of insects, and here also I have found a similar structure in a 

 corresponding position. 



With reference to this a few words may be said as to the 

 structure of the organ in the case of a common wasp ( Vesjxi 

 vulgaris), which perhaps may serve as an introduction to the 

 knowledge of the other forms. In the wasp the structure lies in 

 the small second joint of the antenna, through the middle of which 

 run the main antennary nerve and a tracheal stem. At the end of 

 the first joint the nerve gives ofi" fibrils on all sides, which run 

 obUquely towards the periphery of the second joint, there to enter 

 into connexion with ganglion-cells. These ganglion-cells are also 

 connected with long rod-like structures, wliich run as far as the 

 arthrodial membrane between the second and third joints, where 

 they apparently enter into small pores in the membrane and there 

 end. Into each of these pores or small tubes enters a little group 

 of these structures, which I will here term rodlets (Stabchen). 



* Johnston, " Auditory Apparatus of the Ciilex Mosquito," Joiirual 

 of Microscopical Scionce (Old Series), vol. iii. 1855. 



+ Mayer, " Eesearehes in Acoustics : Paper no. 5," * Philosophical 

 Magazine' for Deconibor 1874, p. 513. 



I Woismanu, " Dio Metamorphose von Corethra plumicornis," Zeitschr. 

 f. wiss. Zool. xvi. 1V\. 



§ Hurst, " The Pupal Stage of Culev," Inaug. Dissertat. Leipzig, 

 1890. — "On the Life-Ilistory and Development of a Gnat." Transactions 

 of the Manchester Microscopical Societv, 1890. — "The Post-embrvouic 

 Development of Culex,'' Proceedings of the Liverpool Biological Society, 

 vol. iv. 



