THE POTATO TTJBEE MOTH, 



37 



The pupa (fig. 23) is very flat and black. Several individuals may 

 issue from one host. Under field conditions about equal numbers, 

 of males and females 

 issued, but in the labo- 

 ratory males greatly 

 predominated. Mating 

 takes place as soon as 

 the adults issue, and 

 oviposition shortly 

 after. The females (see 

 fig. 24) probably obtain 

 moisture from the 

 wounds made in the 

 epidermis of the leaf by 

 their ovipositors, as 

 they were often noted 

 after oviposition to 

 backup and apply their 

 mouth parts for some 

 time to the hole made 

 in the leaf. As the 

 tuber-moth larva had 

 generally moved away by this time, it could not have been possi- 

 ble for it to have obtained food from the wound in the larva. 



Fig. 21. — Sympiesis 

 stigmatipennis: 

 Immature larva 

 feeding on larva 

 of tuber moth. 

 Much enlarged. 

 (Original.) 



Fig. 22. — Sympiesis 

 stigmatipennis; 

 Mature larva. 

 Much enlarged. 

 (Original.) 



Fig. 23. — Sympiesis: 

 s tig mat ipennis: 

 Pupa. Much en- 

 larged. (Original.) 



Fio. 24. — Sympiesis stigmatipennis: Female. Much enlarged, (f)riginal.) 



This parasite issued in groat numbers in 1014 and 1915, and gives 

 promise of doing much to control tiie h^af-mining tuber worm. The 

 following record gives an average life cycle: 



1915. 

 .January 2fi. — Tubf;r-rrK)th larva j)ara.4ilizc(l Ijy iSyrnpicsi'i siUjrnalipenm.8. 

 February 21. — 3 Sympiesis stigmatipennis adults iHsued. (Males.) 



