I20 Annals Entomological Society of America [Vol.1, 



nerves (Fig. 2, tr. n.) Each transverse nerve of the third thoracic 

 ganghon gives off a small mesal branch, which innervates the 

 small transverse muscles of this region. Before reaching the 

 tracheal nerve, the last mentioned transverse nerve receives 

 branch 5 of the lateral nerve trunk of the first abdominal ganglion. 

 As a rule, the median nerve of each abdominal segment extends 

 caudad to the anterior border of the following ganglion (Fig. 3). 

 Here it terminates in an enlargement, which may be the ganglion 



OF THE MEDIAN NERVE* {mg) . 



The transverse nerves are two in number for each median 

 nerve. Each extends laterad receiving branch i of the lateral 

 nerve and forming with it a single nerve, which connects with 

 the tracheal nerve. 



Exceptions to the above typical condition occur in the first 

 and seventh abdominal segments. The median ner-\'e of the 

 former does not give rise to any transverse nerves (Fig. i) and in 

 the latter the median nerve does not reach the following ganglion 

 but terminates in the two transverse nerves (Fig. 10). 



As stated in connection with the mandibular nerve, a minute 

 ganglion is to be found at the base of the mandible, (Fig. 6), 

 forming a part of the sympathetic system. The main nerve 4 

 enters the mandible and gives off four branches. The caudal 

 termination of nerve 4 has not been traced. Nerves 6 and 7 are 

 also part of this system. Branch 2 connects the ganglion with 

 the central system. 



BIBLIOGRAPHY. 



Berlese, A. '07. Gli Insetti, loro organizzazione, sviluppo, abi- 



tudini e rappovti coll'uomo. Milano 1907, Vol. I, Capitulo 



XI, p. 559. 

 Brandt, E. '79. Vergleichend-anatomische Skizze des Nerven- 



systems der Insekten. Horae Soc. ent. Ross. Tom. XV, 



Taf. III-IV, p. 3-19. 

 ■ '79. Ueber die Metamorphosen des Nervensystems 



der Insekten. Horae Soc. ent. Ross. Tom. XV Taf. V-VI, 



p. 20-30. 

 Cholodkowsky, N. '81. Zur Frage ueber den Bau und ueber die 



Innervation der Speicheldrusen der Blattiden. Horae Soc. 



ent. Ross. Tom. XVI, p. 6-9. Taf. II-III. 



* Brandt, 79. 



