286 CAROLINE BURLING THOMPSON 



Jonescu '09 describes, in Apis, fibers from the central body to 

 the^ocellar glomeruli" which he says continue as the ocellar nerves 

 to the ocelli. On page 142 he states: 



Fasern von der Pars intercerebralis (Haller) dringen durch den Zen- 

 tralkorper in die Ocellarglomerulen ein und gelangen dann weiter als 

 Ocellarnervenfasern in die Ocellen. Charakteristisch finde ich einen 

 Theil der Fasern, welche aus den inneren Kapseln des Zentralkorpers 

 kommen und eine Kreuzung vor dem Eintritt in die Ocellarglomerulen 

 bilden (siehe Frontalschnitt Fig. 22). 



As stated above, there is no connection in Bombus or in ants 

 between the ocellar nerve fibers and the posterior roots, the ' 'ocel- 

 lar glomeruli " of Jonescu. The charecteristic fibers which Jonescu 

 describes passing from the central body to the "ocellar glom- 

 eruli" are evidently fibers either belonging to the central body 

 roots of the mushroom bodies, or issuing from the central body 

 to the protocerebral tissue. The term "tubercles of the central 

 body" as frequently applied to the two masses of the posterior 

 roots is also inexact, although less so in Bombus than when applied 

 to ants, for in Bombus, as was shown above, some fibers from the 

 central body accompany the fibers of the posterior roots of 

 the mushroom bodies. In this genus the term "tubercles of the 

 central body" is not altogether incorrect, but is misleading, and 

 in the opinion of the writer, should be abandoned, together with 

 its synonym "ocellar glomeruli," in favor of the term "posterior 

 roots of the mushroom bodies." 



Figures 6, 7 and 8 show the commissure, or horizontal fiber 

 tract connecting the right and left protocerebral lobes, which was 

 termed by Jonescu for Apis the"Ocellarnervenbrucke,"but which, 

 as found in ants, has been named by the writer the "posterior 

 dorsal commissure." This term, rather than " Ocellarnerven- 

 briicke," should be applied to the structure found in Bombus, 

 figures 6, 7, 8, p.d.cm., since the ocellar nerve fibers l.oc.n., pass 

 to the protocerebral fibrous core through the commissure and not 

 along it. Von Alten, 1910, text-figure 4 a, has figured the same 

 relative arrangement of fibers in the brain of the Bombus queen. 

 Jonescu, however, finds that in the honey bee the ocellar nerve 

 fibers go to the protocerebral lobes by the way of the posterior 



