ON THE LIFE HISTORY OF UGIMTA. 17 



III, fig. 1 m m ) which are separated from the canal by the interposition 

 of the silk glands ( Fl III, fig. 1 h ). 



A single silkworm has usually one or two of its ganglia infested 

 by the maggots; but sometimes more are found : in one case I found 

 five ganglia thus infested by the parasite (PI. Ill, fig. 7 a, h, c, d, e ). 

 Furthermore, a single ganglion may have more than one parasite in its 

 interior. Nevertheless, it is true that almost invariably only one mature 

 maggot crawls out of a single silkworm or cocoon. This is due to two 

 reasons: Ist^ the silkworm, when infested by more than one maggot, 

 dies from not being able to endure the injuries caused by these para- 

 sites, which then perish by a kind of suicidal death. 2nd, one among 

 several maggots infesting the same silkworm may grow more actively 

 and rapidly than the others, which will then die from the want of 

 requisite food. 



When the maggots once infest the ganglia, tlie silkworm becomes 

 generally weakened, and its body presents an unusual aspect from 

 severe irritation of the nervous system. The segments are swollen out 

 like the caterpillars of some hawked moths, and the disease is usually 

 known by the silkworm growers as Fushidaka or Fushiko {swelled seg- 

 ment ) ( PI. Ill, fig. 3, 4, 3) This disease however is not always due to 

 the parasite, but may be occasioned by several other causes, especially 

 pebrine. Rarely, silkworms infested by the parasite show no marked 

 indication of illness for a long time. 



Tliat the mnggots chiefly infest these ganglia which lie close be- 

 neath the digestive canal of the silkworm, is easily seen by laying open 

 several infested specimens. In most cases, those ganglia in which the 

 maggots are lodged are anteriorly those of the second to the fifth or 

 sixth segments, and posteriorly those of the eighth or ninth to the last. 

 The intervening ganglia of the middle segments, being separated from 

 the digestive canal by the large paired silk glands, are, as already stated, 



