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TEXT-BOOK OF ENTOMOLOGY 



portion radiated." In the locust there are but two divisions of the 

 calyx ; in the cockroach, ants, wasps, and bees, four. 



The shape and relation of the mushroom bodies are represented 

 in Figs. 252 and 253. The bodies are connected by commissural 

 fibres, and are connected with the optic ganglion of the same side, 

 and with the central body; while they are connected with the 

 antennal lobes by the optico-olfactory chiasma. 



The stalked bodies are 

 enveloped by the cortical 

 layers of ganglion-cells, those 

 filling the hollow of the calyx 

 having little or no proto- 

 plasm around the nucleus. 



Structure of the mushroom 

 bodies. By staining the brain 

 of the honey bee with bichromate 

 of silver, Kenyon has worked out 

 the structure of the mushroom 

 bodies, with their cells. The cup- 

 shaped bodies or calyces are 

 composed of fibrillar substance 

 (punktsubstanz} . Each of these 

 cups, he says, is "filled to over- 

 flowing with cells having large 

 nuclei and very little cytoplasm." 

 From the under surface of each 

 of these cups there descends into 

 the general fibrillar substance of 

 the brain "a column of fibrillar 

 substance, which unites with its 

 fellow of the same side to send a 

 large branch obliquely downward 

 to the median line of the brain, 

 and an equally large or larger 

 branch straight forwards to the 

 anterior cerebral surface." 



The cells of the mushroom 



com 



gc.trit.l 



UUb.fr- 



lr.com- 



oe.com 



Fio. 251. Sagittal section through the brain of the 

 locust : I. oc. n, lateral ocellus nerve ; a. t, anterior tuber- 

 cle of the mushroom body ; i. t, internal tubercle of 

 the mushroom body ; c. I, cerebral lobes ; 1. 1, lateral 

 lobe of the middle protocerebrum ; corn, commissural 

 cord ; c. mol, central mass of the olfactory lobe ; <ic. mi. 

 I, fibres uniting the median lobe of the middle protocere- 

 brum with dorsal lobes of the deutocerebrum ; fire. frit, bodies, observes Kenyon, "stand 

 /, tfaiitflionatcd cortex of the tritocerebral lobe ; c. an. t, t _u Qrr . f)r . T1 f r o t tr> all nthpr 

 cortex of antennal (olfactory) lobe; /,//<../>. labrofrontal out m snai P contrast to all other 

 IM i \r ; oe. com, cesophageal commissure ; tr. corn, trans- nerve cells known, though they 

 VI-I-M' commissure of oesophageal ring; other letters as ., u f 



in Fi-. 250. -After VlallanesT reca11 to some extent the cells of 



Purkinje in the higher mammals. 



Each of the cells contained within the fibrillar cup sends a nerve-process into the 

 latter, where it breaks up into a profusely arborescent system of branchlets, 

 which often appear with fine, short, lateral processes, such as are characteristic 

 of the dendrites of some mammalian nerve-cells." Just before entering the 

 fibrillar substance, a fine branch is given off that travels along the inner surface 

 of the cup along with others of the same nature, forming a small bundle to the 

 stalk of the mushroom body, down which it continues until it reaches the origin 



