Protocerehrum of Micropteryx. 133 



not, then, a new discovery, but I trust that I have been 

 enabled to put the homologies of the matter on a sound 

 basis. 



IV. The Central Body. 



The central body of Micropteryx consists of two capsules ; 

 the larger of these, the outer {ou. ca.), is superior and 

 posterior, the smaller or inner capsule {in. ca.) is inferior 

 and anterior. They are respectively the dussere SchaJe 

 and inner e Schale of Kiihnle. They lie together in that 

 space in the middle of the protocerebral lobes to which 

 Viallanes gave the name la loge; this contains also the 

 ocellary glomeruU and the inner roots of the mushroom body 

 (PI. VIII, figs. 7-10). The space is bounded on all sides by 

 the protocerebral lobes, and above by the tract/,- in front 

 by the tract c, behind by the tract d, and below by the 

 double tract e (see p. 137). 



Micropteryx is one of those insects in which the central 

 body is large and the mushroom body comparatively small ; 

 that is to say, it falls within one of Bretschneider's lower 

 categories. 



The outer capsule is slightly wider than the inner. The 

 anterior edge of each is in the same vertical plane, but the 

 outer extends back a considerable distance behind the inner, 

 and this posterior part of it is very thick; thus the outer 

 capsule overlaps the inner above and behind and is much 

 the more bulky of the two. This condition is character- 

 istic of nearly all the insect brains which have yet been 

 described. Turning to internal structure we find that the 

 outer capsule stains rather more deeply wath eosin or 

 orange G than do the protocerebral lobes. There is no 

 definite division of either capsule into bodies like the rays 

 of a fan, a condition which has been described in the brains 

 of various insects since the time of Dietl. _ The anterior 

 part of the inner capsule is, however, divided into a number 

 of small rounded masses arranged in no definite manner 

 and separated from one another by bands of axons, the 

 great majority of which pass into the outer capsule. These 

 masses resemble to some extent the glomerular bodies 

 {Faserhdllchen) of the antennary lobe. The scattered 

 naurogUa cells which lie in the space w^hich surrounds the 

 central body are referred to elsewhere (p. 120). There is 

 no group of cells which can be said to belong to the central 

 body either here or in any other insect, and we believe that 



