trolled by a set of muscles which cause it to alternately expand and contract, very 

 much like the bulb-syringe used by physicians. When the muscles expand a vac- 

 uum is created, and the fluid is drawn up from the honeyed chalice of the flower 

 into the receptacle in the head; when they contract, a valve in front closes, a valve 

 behind opens, and the honey in the receptacle is forced backward through the 

 oesophagus into the crop, and thence into the stomach. The stomach lies on the 

 ventral or under side of the body, but above the nervous cord, which lies still more 

 ventrad. The stomach opens posteriorly into the small intestine, which is followed 

 by the colon, the latter in turn being succeeded by the rectum. Connected with 

 the intestines are certain vesicles, which are known as Malpighian vessels, and by 

 some are thought to have the function of the liver in higher animals. 



Having thus briefly spoken of the nutritive system we may turn to the circu- 

 latory and respiratory systems. The heart of a butterfly, as in all arthropods, lies 

 on the dorsal side of the body. Its location corresponds almost exactly to that 

 occupied in the vertebrate animals by the spinal cord. It is a long tubular organ. 

 It does not possess chambers ventricles and auricles such as are discovered in 

 the heart of vertebrates, but it has an enlargement in the mesothoracic region known 

 as the aortal chamber. The movement of the heart is wave-like, analogous to the 

 peristaltic movement in the intestines of the vertebrates . From the heart there go 

 out lateral blood-vessels, which ramify and intermingle with the capillary extremi- 



24 



