276 CE^ 7 ERAL ANATOMY OR HISTOLOGY OF BLOW-FLY. 



some with two or four nuclei, in which fat granules are abun- 

 dant. These are the proliferating cells from which the fat 

 bodies are developed. 



In the mature Insect, cell-capsules (mother cells), containing 

 hardly any fat granules, or entirely exhausted, are seen 

 amongst the fat cells, and contain a reticulum of stellate 

 nucleated cells, closely resembling the segmentation cells of 

 the food-yelk (PI. XVI., Fig. 8). 



Intercalated Cells. The fat bodies of many Insects have 

 peculiar pigrnented cells scattered amongst the fat cells. 

 Graber describes these as containing yellow or green granules 

 and rod-like crystals, and he regards them as imperfectly 

 developed fat cells. I have never found such cells in either 

 the larva or imag'o of the Blow fly, unless the cell-capsules of 

 exhausted fat cells (mother cells), which contain the stellate 

 cells described above, are their representative. If this be so, 

 Graber's ' eingesprengte Zellen ' are more probably exhausted 

 than imperfectly developed fat cells. I have not had an oppor- 

 tunity of examining the insects in which intercalated cells are 

 described by Graber and others. 



Oinocytes. This term is applied by Wielowiejski to certain 

 chains of cells which occur a pair in each segment imme- 

 diately beneath the integument in the larvae of some Diptera, 

 which he regards as representing the intercalated cells of the 

 fat bodies. This interpretation of their nature is, I believe, 

 incorrect. Nor is the term ' oinocyte ' a good one, as it has 

 also been used for the intercalated cells of the fat bodies. 



Wielowiejski says: 'The oinocytes in the Brachycerse re- 

 semble those of Chironomus, and are situated in the same 

 position, at the sides of the abdominal segments.' He 



The reader may consult the following papers on the origin and nature of 

 Oinocytes (Wielowiejski), and Intercalated cells, Schaltzellen (Leydig) : 



137. GRABER, V., ' Ueber den propulsatorischen Apparat. der Insecten.' 

 Archiv f. mikr. Anat., Bd. xi. 



138. WIELOWIEJSKI, H. RITTER VON, ' Studien riber Lampyriden.' 



Zeitsch. t. w. Zool., Bd. xxxvii., iSSi. 



139. EMERY, ' Ueber die Leuchtorgane von Lampyris italica? Zeitsch. 



f. w. Zoo!., Bd. xl., 1884. 



