J 



8 WHEELER. [Vol. VIII. 



A section from a very young nymph (lo mm. long), is shown 

 in Fig. 65. The cytoplasm of the fused cells is reduced 

 to a ragged mass in which the irregular nuclei are suspended. 

 Their chromatin is aggregated in rounded masses — a sign of 

 advanced degeneration. In this stage the organ is much 

 shrunken in size so that one is led to conclude that part of it 

 has already been absorbed. In a little later stage the last 

 traces of the organ have disappeared. 



A suboesophageal body essentially like the one here described 

 occurs also in Blatta. It, too, has the characteristic yellow 

 tint. In his study of the development of Blatta Cholodkowsky 

 appears to have seen this peculiar structure, though he regarded 

 it as a portion of the fat-body. At page 52 ('91^), he says: 

 "Die Entodermlamelle umwachst den Nahrungsdotter dorsal- 

 warts und von alien Seiten; der Vorder- und Hinterdarm 

 liegen nun ausserhalb des Nahrungsdotters und werden vom 

 homogenen Dotter umsptilt, in ivclcJiem {bcsojiders iiebcn dcm 

 CEsopJiagiis) kleine blasse Zcllcn licgcn, die sick in Fcttkorpcr zii 

 verzvatideln scJieiiien!' ^ The organ is shown in Cholodkowsky's 

 Fig. 68, PI. VI. In other writers on insect embryology I find 

 no mention of this interesting structure. 



In the Rhynchota, to judge from a few observations on the 

 embryos of ZaitJia fluminea, the suboesophageal body occurs in 

 a slightly modified form. Here it consists of a number of loose 

 spherical cells lying on either side and a little below the 

 oesophagus. The nuclei are large and spherical and the com- 

 pact and finely granular cytoplasm has a distinct yellow cast. 

 Though these cells vary in size (i i-15/x) they are always larger 

 than the cells of the surrounding tissues (6.3/u,). Beyond this 

 stage I could not trace the organ in Zaitha on account of lack 

 of material. 



The suboesophageal body may always be readily distinguished 

 from the fat-body of the oral and more posterior segments by 

 the peculiar structure and arrangement of its cells and by its 

 yellow tint. I therefore regard it as an organ siii genesis. It 

 belongs to the category of embryonic or early larval organs, 



^ The italics are mine. 



