no Annals Entomological Society of America [Vol.1, 



The Suboesophageal Ganglion (Figs. 2, 5, and 7, s.g). The 

 suboesophageal ganglion is situated below the oesophagus in the 

 anterior portion of the head. It is a rather large ovoid ganglion 

 with its caudal portion terminating in the two connectives which 

 pass back to the first thoracic ganglion. 



From the suboesophageal ganglion there arise the following 

 nerves : 



The mandibular nerve (Figs. 4, 5, 6, and 7, md) . The 

 mandibular nerve arises as a large nerve trunk from the upper 

 part of cephalo-lateral border of the suboesophageal ganglion. 

 For a distance of a few millimeters it runs cephalad underneath 

 the pharnyx, then it turns dorso-laterad until reaching the level 

 of the optic and antennal nerves. Here it projects laterad, 

 passing in front of the column-like apodeme (ap), where it 

 divides into three branches. 



Branch i bends caudad and innervates the large mandibular 

 muscles. Branch 2 is quite short and slender, and connects 

 the mandibular nerve with a minute ganglion (g) . This ganglion 

 has been observed in several specimens and probably forms a 

 part of the sympathetic system. The third branch of the man- 

 dibular nerve has two prominent ramifications, of which the first, 

 labeled 5, enters the mandible while the second, marked 7, runs 

 laterad until approaching the outer condyle of the mandible, 

 where it divides, sending oft' one anterior smaller branch to this 

 part of the head and one larger caudal branch to the mandibular 

 muscles. 



Nerve 4 has not been found connected with the central ner- 

 vous system. It and the ganglion (g) will be discussed under 

 the sympathetic system. 



The maxillary nerve (Figs. 4, 5, and 7, mx) . The maxil- 

 lary nerve arises from the cephalo-lateral border of the sub- 

 oesophageal ganglion. It is a rather large nerve trunk, project- 

 ing cephalad for the distance of a few millimeters, after which it 

 breaks up into four branches (Fig. 5 mx.) The most proximal 

 of these branches consists of a small nerve extending laterad to 

 the base of the maxilla. The three remaining branches all 

 originate from the same level shortly cephaled of the first branch. 

 The two branches of the fourth, and also the anterior branch of 

 the third, enter the maxilla. The second branch terminates in 

 the enlarged basal portion of this organ. 



