224 WILSON P. GEE. 



as being metamorphosed into the fat-body, and also as giving 

 rise to the Hood corpuscles. 



\Yheeler (1892) in an extensive paper on the blood tissue of 

 insects deals with the oenocytes at considerable length. He ar- 

 rives at the following conclusions: 



1. "The oenocytes are derixcd by delaniination from the ecto- 

 derm just caudad to the tracheal involutions They are also 

 metameric organs. 



2. 'They are limited to the eight trachigerous abdominal 

 segments. 



3. 'They appear to be restricted to the Pterygota, in all the 

 members of which group they probably occur. 



4. 'They give rise neither to the fat-body nor to the blood 

 but represent organs sui generis. 



5. "Alter their differentiation from the primitive ectoderm, 

 they never divide, but gradually increase in size." 



\\ itli regard to their function, the only suggestion that Wheeler 

 makes is in his discussion of their vacuolate structure in certain 

 of the larva? of the Trichoptera. Here he says: "One is re- 

 minded of certain gland cells which store up vacuoles of a specific 

 substance in their cytoplasm, preparatory to secretion." 



Heymons (1895) in the embryogenesis of Forjicuhi, points out 

 that the oenocytes are found in the eleventh abdominal segment 

 as well as in the others. The eleventh segment bears no stigma, 

 and thus they cannot bear any relation to the stigma as such. 



Pantel (1898) classes the oenocytes as an organ because of 

 their metameric repetition, and treats to a slight extent of their 

 cytological changes in different periods of the insect's life. He 

 hesitate^, lumever, to commit himself as to their function, but 

 rather inclines toward the excretory phases of their probable 

 act i\ il ies. 



Berlesc (1*99), in his work on tin- ants, 7 \i /uiionui erratic nnt 

 ;md I'hcidole pallid/ilu, finds that, in the beginning of mei.i- 

 morphosis, the larval u-nocytes are multiplied, give up their 

 lixed position, and, becoming amu-boid, are scaiterrd about 

 among the fat-bodies. In his work on Politics 'jalllca and on the 

 honey-bee, he ImiU a persistence of the o-nocytcs, \\itli no special 

 second generation. Their function he considers as excretory, 



