22 NOTES ON A SPECIES OF SANDFLY 



or four times up and down on account of their length. On 

 these, at regular intervals, large glandular cells are placed. It 

 is thought that these tubes fulfil functions similar to the liver 

 in animals. 



The nervous system consist of the brain and six ganglia 

 united by a double cord of nerves. From each side of these 

 nerve reservoirs branches proceed, which ramify to different 

 parts of the body. The last ganglionic mass in the abdomen is 

 double the size of those preceeding it, as it has to supply the 

 organs of reproduction, as well as the neighbouring structures, 

 with nervous force. 



With regard to the function of respiration a peculiar pro- 

 vision for the reception of air is found in the possession of three 

 air sacs. Two lie in the thorax, and the third extends like a 

 bag to the lower part of thf^ abdomen. They are attached to the 

 aesophagus near the neck. The two smaller sacs are probably 

 coiupensatory additions, which come into play when the 

 abdomen of the female is distended with eggs. Then the 

 pressure of its contents prevent the expansion of the main air 

 sac, so that it is comparatively useless for the time, (as a mitter 

 of fact I have generally found it almost empty) ; then the two 

 thoracic sacs come into play and retain air for the purposes of 

 lightening the specific gravity, and the respiration of the insect* 

 As in the case of the mosquito the air in the sacs is in the form 

 of minute bubbles, separated from each other by an oily film. 

 The sac walls are very transparent, resist most stains, and con- 

 tain longitudinal and transverse fibres, so that they seem 

 capable of contraction and expansion. The whole of the 

 abdominal organs are subject to a perisaltic movement. They 

 are slowly drawn forward and then thrust backward every few 

 seconds. Thus the process of digestion is aided by the food 

 being moved about in the intestines, and the function of respir- 

 ation is likewise accelerated by the air being forced through the 

 tracheal tubes. 



In the last segment of the female are found two brown oval 

 organs like beans ; these are the spermathfeca, which secrete 

 the gum by which the eggs are united together. The mosquito 

 possesses three, but only two are found in the sandfly. A 

 slender tube passes from each into the lower bowel, so that their 

 contents can be brought into contact with the eggs as they pass 

 from the ovarian duct to be placed on the outside of the body. 

 The egg sacs occupy in the female a large space in the abdomen. 

 One is placed to the left and the other on the right. A large 



