i893- RESEARCHES ON INSECT ANATOMY. 117 



From each cone the nerve-fibre passes along the wall of the tracheal 

 tube, first to a ganglion cell, and then to join the tympanal nerve, 

 which is situated where the tracheal wall comes into contact with the 

 drum (Figs. 5, 6). 



Near the upper end of the crista acustica is situated a mass of 

 nerve-endings which have hitherto been reckoned a part of that 

 structure, but for which Von Adelung proposes the name of " inter- 

 mediate organ " (zwischenorgan) (Fig. 6, i.o.). These nerve-endings, 

 which are connected by nerve-fibres with ganglion-cells, and then with 

 the tympanal nerve, are also in connection with tissue-fibres, by 

 which they are stretched between portions of the integument of the 

 leg. Hence, Von Adelung considers them related to the rods of the 

 chordotonal organs described by Gruber (4) as well as to the nerve- 

 endings of the supra-tympanal organ which forms the remaining 

 portion of the ear of the long-horned grasshoppers. 



This supra-tympanal organ consists of two groups of elongated 

 rods stretched across within the tibia above the region of the drums. 

 These rods are connected with ganglion cells. From the ganglion- 

 cells of the lower group fibres pass to the tympanal nerve, while those 

 of the upper group are connected with a special supra-tympanal 

 nerve, which, like the tympanal, takes its origin from the main tibial 

 nerve (Fig. 6, s.t.o.). 



An interesting paper on the structure of insect-wings has recently 

 appeared. Hofifbauer (5) nas investigated these organs by means of 



E.VPLANATION OF FIGURES. 



Fig. I. — Longitudinal section through head oi Mdophagus (proboscis retracted). 



2, — Mouth-parts of Bvaida (front view). 



3. — Do. (horizontal section.) [All after Miiggenburg.] 



cl.— clypens. mx." — maxillae (second pair) (or labium). 



Ibr. — labrum. o. — oesophagus, 



mx.i — maxillae (first pair). s.— duct of salivary gland, 



mx.ij — Do., when proboscis is exserted. sp. g. — super-cesophageal ganglion, 

 mx. p. — Do., palp. sb. g. — sub-oesophageal ganglion. 



Fig. 4. — Sketch of tibia of a Phasgonurid, to show position of ear apertures. 



5.- — Transverse section of tibia. 



6. — Longitudinal section, showmg parts of ear. [All after von Adelung.] 

 fe— femur. s.t.n. — supra-tympanal nerve, 



tib. — tibia. tr. — tracheae. 



a. — external apertures. i. o. — intermediate organ. 



b. — outer auditory chambers. s.t.o.j — supra-tympanal organ 



ty. — tympana. (upper division). 



c. a. — crista acustica. s.t.o..^ — supra-tympanal organ 



tb. n. — tibial nerve. (lower division), 



ty. n. — tympanal nerve. 



Fig. 7. — Transverse section through sutural edg'' of elytron of a Chrysomelid beetle 



[Lima puli). [After Hoflbauer.] 

 o. — upper surface. tr. — trachea, 



u. — under do. gl. — glands, 



s. ^sutural edge. 



