(SO iSciiteniber, 



species in searching for nectaT, carrion, or other organic alimentary 

 substance, or when feeding or ovipositing. AVhile then there is nothing 

 alleged to disprove high olfactory adaptation in the antennae, vre might, 

 with Cuvicr, in certain cases {Diptera ?) discover such a power in the 

 spiracular adits, or, with Burmeister and Huber, more doubtfully trace 

 it in the oral parts : yet, when we turn to other portions of the trunk 

 accredited with sensibility to sound, we certainly find organs more 

 adapted for audition. 



Treviranus (1809) discovered white spots at the antennal base, 

 which Burmeister and others consider to be rudimentary eyes 

 {stemmata) ; these appear to be the organs Comparetti held to be 

 auditory. Clarke (1S3S) also found auditory structures at the 

 antennal base, which later investigators have not confirmed. The 

 more important organs at the abdominal base of the AcridiidcB and 

 their homologues on the fore tibise of the LocustidcB I have already 

 alluded to (Ent. Mo. Mag., vol. xiv, pp. 121 — 126). Several papers 

 have appeared in German periodicals confirming the general descriptive 

 lines laid down by Muller and Siebold (1855, Leydig, Archiv. fiir Anat. ; 

 1866, Hensen, Zeits. fiir wiss. Zool. ; 1874, Vitus Graber, Mittheil. des 

 naturwiss. Vereines fiir Steiermark ; 1875, Oscar Schmidt, Archiv. fiir 

 Mikro. Anat.; 1876, Vitus Graber, Denkschrift. der Kaiserlich. Akad. 

 derWissens.), and treating of specific modifications of the organs, their 

 development during metamorphosis, the structure of their tissues, and 

 homogeneity of the Acrideous tympanum with the integument. Vitus 

 Graber (Deukschr., pp. 284 — 293) argues that the tibial modifications 

 of the GryUidce and Locustidce are absent in mute species, indirectly 

 showing that it is here chiefly small abdominal membranes are found ; 

 these he docs not regard as auditory, nevertheless, adopting in lieu a 

 somewhat quaint theory of Dr. Landois (Zeits. fiir wiss. Zool., b. xx). 

 In my paper above-mentioned I stated that I detected the structural 

 elements of the Orthopterous organs in Lepidoptera, and hazarded 

 a conjectm^e that the "mirrors" of the Clcadidce were auditory. These 

 last, since the days of Eeaumur (Mem., v, 178), have been neglected, 

 being considered to be " sound magnifiers," and the "membranes" of 

 the AcridiidcB were once similarly accredited (De Geer, Mem., 

 iii, p. 429). I will now, therefore, attempt a description of their struc- 

 ture and nervous connections. 



The mirrors of the Cicadidce (membranse tympanicoe), generally, 

 consist of a membrane surrounded with an outwardly hollow chitinous 

 frame. Among the males this approximates in form a harp-shaped 

 triangle, situated at an angle with the median plane, so that the apex 



