128 



The pericardial cells are extremely large cells 

 lying on either side of the dorsal vessel throughout 

 its whole extent. They are by far the largest cells 

 in the mosquito, varying from 30/4 to 50^ in longitudinal 

 diameter. They are elongate or pear-shape in form, 

 and contain several nuclei. The nuclei usually show 

 signs of degeneration. The peripheral portion of the 

 cell stains more deeply than the central portion, which 

 contains the nuclei and small stained granules. There 

 is a considerable number of masses of a light yellowish 

 pigment resembling that found in the large visceral 

 ganglia cells. The fibres from the branches of the 

 alary muscles pass over and around the pericardial 

 cells to reach the dorsal vessel. From their structure 

 and situation the pericardial cells appear to be of the 

 nature of ganglion cells (Fig. 40). 



The Fat-body. The fat-body, both where it 

 occurs as a portion of the body wall and where it 

 lies as free lobulated masses, consists of cells containing 

 numerous oil globules. The cells are of considerable 

 size, and their borders may be frequently traced 

 as polygonal areas. The nuclei are oval in shape with 

 a central mass of chromatin and chromatin threads. 

 Besides oil globules the cells contain granules staining 

 with haematein, and minute droplets of a highly 

 refractive, dark substance, which gives the appearance 

 of pigment. These droplets are larger in amount in 

 old mosquitoes than in those freshly hatched (Fig. 40). 



The Re-productive System. Each ovary consists 

 of a large number of follicular tubes whose lower ends 

 open into the ovarian tube, and whose upper ends 

 terminate in a delicate supporting filament (terminal 

 filament). The apex of the ovary is formed of a 

 single follicular tube, whose filament is attached to 

 the fat-body of the fourth segment. 



