572 



GEORGE H. BISHOP 



from the intestine to the nerve cord. From here it extends 

 dorsally in two chief layers, the intestinal layer just failing to 

 close over the gut dorsally, and the margins of the parietal layer 

 adjoining on either side the dorsal blood vessel. Through the 

 transparent chitin of the grown larvae may thus be seen a clear 



'■fe<:A>^ >-^ 



Text fig. A One half of a cross-section of a mature bee larva, ht., heart; 

 h.s., haemal space; int., mid-intestine; n., ventral nerve cords; sp., spinning 

 glands; m.t., malpighian tubules; m., muscles; exc, excretory cells of the fat- 

 tissue; oe., oenocytes. The remainder of the cells, not shaded, are the fat-cells 

 or trophocytes. The cells of this tissue are arranged in folds or laminae, each 

 .two to five cells thick; the lamina run in general longitudinally in the body and 

 are separated by blood spaces, which also surroimd all the organs. The oenocytes 

 and excretory cells, both amoeboid, lie sometimes completely embedded in the 

 fat-tissue, sometimes along the margins of the blood spaces. Roughly, three 

 regions may be distinguished: a visceral or splanchnic layer of the tissue ventral 

 and lateral to the intestine; a parietal layer along the body wall, ventral and 

 lateral; and a cardiac layer, extending from the heart region lateroventrally 

 on either side the dorsal haemal space. These layers correspond to the three 

 mesoblastic anlages of this tissue in the embryo. Camera-lucida drawing. 



blood space below the dorsal heart and pericardium, and through 

 this again is visible the yellowish content of the mid-intestine, 

 flanked on either side by white fat-tissue (text fig. A). 



In cross-section the fat-body is seen to be longitudinally lami- 

 nated, each lamina tw^o to five cells thick, and extending from the 

 central or peripheral layer into the blood space. A large pro- 

 portion of the cells thus lie in immediate contact with the blood. 



