THE POTATO TUBER MOTH. 



41 



Tlie record of a shorter life cycle follows : 



1913. 

 September 15. — Tuber-moth larva parasitized by Habrobracon johannseni. 

 September 18. — Parasite larvae nearly mature. 

 September 19. — Parasite larvte spinning cocoons. 

 September 20. — Parasite larvae pupating. 

 September 25. — 4 parasite adults issued. 

 September 26. — 17 parasite adults issued. 

 Life cycle 10 days at an average mean temperature of 78° F. 



CHELONUS SHOSHONEANORUM VIER.^ 



This parasite (fig. 29) has been consistently abundant every year from 

 1912 to the present time. Efforts to rear it from the larvae and 

 pupae of the tuber moth 

 failed, and, at the sug- 

 gestion of Dr. Howard, 

 the insect was placed 

 with eggs of the tuber 

 moth. Oviposition (fig. 

 30) took place at once, 

 the parasites usually 

 feeding on the moisture 

 which collected at the 

 wound caused by the 

 ovipositor. 



The eggs of the tuber 

 moth hatched normally, 

 and the young larvae at 

 once burrowed into the 

 tuber. Later the mature 

 tuber-moth larvae began 

 to leave the tuber and start their cocoons. Some of the larvse ap- 

 peared restless and darkened spindles were noticeable in their bodies 

 (fig. 31), quite similar to those in the case of Campoplex 'plitliorimaeae. 

 None of the larvae pupated, and soon the mature parasite larva (fig. 32) 

 emerged and spun its white cocoon within the cocoon of its host. 



This parasite promises to be of value in controlling the tuber moth 

 in the field. It apparently does not work in darkened bins,. 



The life cycle is divided as follows: 

 1914. 



July 20. — Tuber-rnoth eggs parasitized Ity (,'hclonus shoshoneunorum. 



July .'II.— Tiiber-irioth eggs hatched. 



August 10. — ChelonuM larv;* mature. 



August JH. — ('hahmuH larvix; pupating. 



August 26. — I (-'helonuH adult i.s.4ued. 



August 27.-3 Chelonas adults iH.Hued. 



August 28.-2 r'holonus a<lults issued. 



Life cycle 31 days at an average mean temperature of about 72° F. 



Fig. 31. — Larvae of tuber moth para- 

 sitized by Chelonus sJioshoneanorum. 

 Much enlarged. (Original.) 



Fig. 32.— Chelonus slio- 

 shoncanorum: Mature 

 larva. Much enlarged. 

 (Original.) 



I Chltlcndoii No. 'iXm". 



