THE POTATO TUBEK MOTH. 



33 



PARASITES. 



Pai'asites vary in effectiveness. During 1914 Habrobracon johann- 

 seni (fig. 16) was the most effective, and the following list probably 

 gives them in the order of their importance for that year : 



Habrobracon johannseni Vier. 

 Chelonus shoshoneanorum Vier. 

 Sympiesis stigmatipennis Girault. 

 Campoplex pTithorimaeae Cushm. 

 Bassus gibbosus Say. 



During early 1915 Dihrachys clisiocampae Fitch was discovered, 

 and while not so well distributed, it seems to be well fitted to be an 



Apantales sp. (Ghttn. No. 2230°^)., 

 Microgastersp. (Chttn. No. 2230"»). 

 Nepeira benevola vav . fuscifemora Cushm. 

 Zagrammosoma flavolineatum Cwfd . 



Fig. K.—Emitty cocoon of the potato tuber moth (large one) and cocoons of its parasite, Habrobracon 

 johannseni. Much enlarged. (Original.) 



effective enemy. Ranking the parasites in the order of their im- 

 portance for 1915 would give them the following order: 

 DihrachjH clisiocampae ] Chelonus shoshoneanorum. 



Sympiesis stigrruitipennis r\^llrLnce!''' 

 Campoplex phthorimaeae) 

 Apanleles sp. (Chttn. No. 2230°^). 

 Ilahrohracon johannseni. 



The last four species in each list were relatively unimportant 

 <lurii)g botli years in the districts from whicli material was collected 

 for study. These were as easily reared in confinement as most of 

 the (others, and there seems to bo no reason why they should not be 

 important equally with other species which oviposit in the tuber 

 lar\'ii wlufre it occurs as a leaf-miner. 



Bassus gibbosus. 



Microgaster sp. 



Nepeird benevola \ixr . fuscifemora. 



Zagrammosoma Jlavolineaium. 



