462 THE XERVOUS SYSTEM. 



Bombus) [170], and also in Sphex and the Formicidae ; he 

 termed them ' Disques radies.' Leydig described them in 

 Vespa [42], Dietl in Acheta domestica and Gryllotalpa [175]; 

 and Flogel discovered them in Blatta [177]. Flogel demon- 

 strated the presence of these organs in a more rudimentary 

 form in the Coleoptera. Whilst Bellonci [183] and Cuccati 

 [186] first described them in the Diptera. 



The calices, in those groups in which they remained longest 

 unknown, arc distinguished by the remarkable fineness of their 

 constituent fibres. Hitherto the only insects in which they 

 have escaped detection are the Hemiptera, and it appears 

 probable that they really exist in these, which in many other 

 points resemble the Diptera. It is usually stated that they are 

 absent in the Crustacea, but similar structures are certainly 

 present in the Crayfish (Astacus), on the sides of the meso- 

 cerebron, as has been already stated (p. 445). 



The corpora fungiformia are relatively largest in the 

 Orthoptera, when compared with the rest of the brain. In 

 the Crickets there is only one calix in each hemisphere (Yial- 

 lanes [185, Mem. 5]). In the Bee, Wasp, and Ant, these 

 organs are very large and readily separate from the surrounding 

 gray matter, so that they are seen as distinct bell-shaped pro- 

 jections, which were figured by Uujardin. 



DKSI -RII' I K >N OF I'l.ATK XXXIII. 



FIG. I. A frontal section of the brain of a Blow-fly through the posterior part of the 

 corpus centrale. This section is somewhat oblique, the right side slightly behind 

 the left side. The external corpus fimgiforme is seen on the left side : /, infra- 

 oesophageal ganglia : ///, mesocerebron ; HI t, internal medulla of the optic 

 ganglion ; /;, trabecula. 



Kic. 2. A section of the internal corpus fungiforme and pyramidal ganglion behind 

 the section seen in Fig. I, from the same brain : cl .r, calix of the internal corpus 

 fungiforme ; i;, great ganglion cells of the pyramidal ganglion, beneath which the 

 roots of the nerve to the ocelli arc seen. The other letters as in Fig. I. 



Fli:. 3. A lateral section through the brain between the oesophagus and the corpus 

 centrale : </, antenna! ganglia ; cr, crural ganglia ; fm, middle capsule ; t <, 

 external, and ;// /', internal medulla of the optic ganglion ; ;///, metacerebron ; 

 o s, optic peduncle ; /, posterior capsule of the optic ganglion ; /</, peduncles of 

 the corpus centrale ; ///, thalamic lobe. 



The two bundles lying in the crural ganglia are the ascending fibres of the 

 crus ; the oval commissure behind the peduncles of the corpus centrale is part of 

 the inferior rommi^iire of ihe mesocerebron. The ascending fibres of the crus 

 are also seen in Fig. i, and the commissure of the mesocerebron in Fig. 2. 



