132 



It will be seen then that an attempt has been made to secure 

 as many parasites as possible to attack each of the different 

 stages of the moths ; and to produce as nearly as possible the 

 same kind of sequence of attack that prevails in the native habitat 

 of these pests — that is, to establish as many as possible of the 

 parasites attacking each of the different stages : egg, larva and 

 pupa. 



Summary of parasites introduced or colonized : Egg Parasites, 

 4 species ; 2 species established. Parasites of caterpillar, 20 

 species ; 7 established. Parasites of the pupae, 5 species ; 1 

 established. A total of 29 species, 10 of which have become 

 established. 



It was confidently expected that several others would be found 

 established when the time came for making the necessary inves- 

 tigations. Some of them were so recently colonized, that it is 

 not expected that it can be determined yet whether established 

 or not, though some additional ones may have been found estab- 

 lished by the investigations in 1911, of which we have no report 

 at hand. 



The situation at present is considered satisfactory, but it is 

 expected that five or six years time may yet be necessary before 

 proof is reached as to whether these two pests can be controlled 

 by the introduced natural enemies. In the meantime, plans are 

 being made to continue the introduction of parasite material. 



In the course of all this work, many observations of extreme 

 biological significance have been made, particularly with regard 

 to the interrelation of host, parasite and hyperparasite. Some of 

 these have already been mentioned, as for instance the five differ- 

 ent methods by which the different Tachinids attack their hosts. 



Another interesting habit is in the case of one of the egg-para- 

 sites from Japan (Sclicdins). The egg of this parasite is sup- 

 plied with a long stalk. It is placed within the body of the un- 

 hatched caterpillar within the egg of the host, but usually with 

 the end of the long stalk projecting outside the host egg. "When 

 the parasite egg hatches, it does not entirely leave its shell, but 

 remains with its anal end thrust into it, and the stalk which is 

 hollow, becomes functional and acts like a life-line attached to 

 a submarine diver in supplying a connection with the outer air." 

 As the larva grows through its two first stages it retains this con- 

 nection with the life-line. This is one of the parasites which 

 also act as hyperi)arasites ; for example, if the host egg had al- 

 ready been parasitized and now contained the full-grown larva 

 of that parasite, it would be the victim of this parasite, which in 

 turn might be destroyed by yet another hyperparasite, according 

 to the conditions in Japan where it came from. 



A more particular hyperparasite is one, that, having gained 

 access to the Ixxly of the host, wanders al)out in search of any 

 parasites that might be there, ap])arently not injuring the host. 



