80 THE CANAiDIAN ENTOMOLOGIST 



shield. The tubercles are not strongly defined, the anal plate of usual pro- 

 minence, brownish, not black. The alcoholic specimen received is discolored 

 from bacterial disease apparently, and details are indistinct. The pupa is nor- 

 mal, glossy and thin-shelled, so that the stigmata, though not brightly white, 

 may be seen before emergence. It is supported in the hollow stem on a cushion 

 of chewed fragments, at a varying distance below the exit orifice. Emergence 

 of adults, Aug. 26 to Sept. 2. Three moths of the series have the stigmata 

 suppressed, in the line of this frequent variation in the genus. 



Papaipema nebris Gn. 



The economic features connected with the introduction of the European 



Corn Borer, Pyrausta nubilalis Hub., have drawn much attention to the larval 

 habit of nebris when it occasionally damages corn ; because of both species 

 being borers, the public frequently assumes to have met the former, whereas it 

 is generally the indigenous species which is concerned. While many of its con- 

 geners will, in the first stages, attack grasses, nebris seems to be the only one 

 that takes up with, and completes its transformations in corn. These attacks 

 are simply invasions, since the females of the preceding year could not antici- 

 pate the following year's location of corn, and it is noticeable also that it is 

 always the borders of plantings which show damage. The entry of the larva 

 is by descent into the head of the leaf whorl, and though the plant continues 

 to grow, the embryonic flower head is destroyed and no ears ever mature. 



The Ambrosiaceae were presumably primitively preferred foodplants 

 with this species; some of these plants, particularly Ambrosia trifida, are apt 

 to occur as weeds at the borders of cultivation, and due to such occurrence, when 

 oviposition may have been numerous at such points, the unplaced larvae of the 

 following season have to shift to whatever may avail them. The point that we 

 wish to emphasize is that whereas nebris normally furnishes an astonishing 

 panorama of parasitism, when working in the preferred Ambrosiaceae, when 

 in corn our observations show an almost entire absence of parasitic attack. 

 The same holds with regard to its accidental presence in any cultivated plant 

 and indicates that it is much to the advantage of the species to make these 

 occasional detours. So keen are its enemies — Macicera senilis, Mg., and 

 Microplitis gortynae Riley, (det. A. B. Gahan), l)eing of chief import in the 

 East — in ferreting out their host that at times total extinction in limited loca- 

 tions result. The parasitized larvae ofifer, in the case of Microplitis particularly, 

 a fruitful field to a secondary following which is numerous in point of species, 

 and efticient in its aid to the central host. There is thus a swinging pendulum 

 of events, registering a rise as nebris gains an ascendency, which may be main- 

 tained for several years, then an abrupt fall when the primary foes have gained 

 their advantage. From this we may gather that, with the adaptability of nebris 

 to so many plants of cultivation, its adventitious establishment in suitable 

 foreign conditions would doubtless bring it into prominence as a first-class 

 pest. • 



An adult Papaipema, undertermined and so far unentountered as a larva, 

 has stood in our series for many years. It was a capture at light and seems 

 to represent an individuality that is not yet recorded. The following name is 

 proposed for it : 



