192 JOUKNAL OF ENTOMOLOGY AND ZOOLOGY 



internal organs separated with needle points. The best results 

 from this method were obtained from formalin fixation, for this 

 reagent left the tissues more transparent and less fused with 

 each other. The tracheae within the nervous system were demon- 

 strated by mounting the freshly removed nervous system to a 

 glycerine solution. The air in the tubes made them clear and 

 conspicuous structures. 



Genekal Form of the Ganglia. The central nervous system 

 consists of a closely fused mass of supra- and sub-esophageal 

 ganglia. From above, the "lirain" forms a nearly spherical 

 dorsal mass. Back of this and below the esophagus, but closely 

 connected with the brain is the fused sub-esophageal and 

 thoracic ganglia. This is not easily seen from above, but when 

 removed from the body it is evident. The globular supra- 

 esophageal ganglion or brain has two pairs of nerves closely 

 associated with its cephalic end. The more dorsal of these is 

 the ocular pair which comes to the brain from the simple eyes on 

 the sides of the head. The more ventral is the mandibular, or 

 rostro-mandibular. 



The sub-esophageal ganglion has four pairs of nerves for the 

 legs and a larger cephalic pair supplied to the pedipalps. This 

 larger branch divides into two within the appendage and one of 

 these parts soon divides again. This is similar to the branching 

 shown by Newport in the pedipalps of the scorpion. Two small 

 nerves extend from the caudal region of the ganglion towards 

 the abdomen. 



Tracheal Supply to the Nervous System. From the cephalic 

 abdominal region two large tracheal tubes run forward a short 

 distance and then break up into bundles of very small branches. 

 Many of these fine tracheoles pass in masses forward to the 

 thoracic and head region and into the central nervous system. 

 Two chief bundles come to the ganglionic mass from caudal 

 regions, the smaller more lateral bundle is more superficial, it 

 divides into two smaller groups of tubules, a lateral and a me- 

 dian. Both of these send tracheoles to the brain and some small 

 strands run beyond up into the upper regions of the head. The 

 more ventral of the two chief bundles of tracheoles also divides 



