10 BULLETIN 1076, U. S. DEPARTMENT OF AGRICULTURE. 
were all isolated before emergence and remained virgins throughout 
their lives, so these figures are doubtless below the normal. 
FOOD PLANTS. 
Unless some food plant other than lotus is inhabited by this insect, 
it is difficult to explain its presence at Kimberlin Heights. From 
present knowledge of its habits it is inconceivable that it came with 
the seeds, and no other lotus is known to exist within possible range 
of flight of this moth. To determine whether the species is indigenous 
or introduced, the writers have made plantings of lotus seed in several 
isolated ponds many miles distant from this infestation. 
Because of the confusion in the literature between this species and 
Pyrausta ainsliei, several food plants have been attributed to it which 
manifestly are erroneous. The only natural food plants which have 
so far been rehably ascertained are the yellow lotus, Velumbo lutea, 
and the Indian lotus, V. nucifera, the latter an introduced species. 
Smith (0, p. 625), mentions having found these larve in stems of 
eat-tail flag, Zyphea latifolia. At Kimberlin Heights conditions were 
ideal for such a transfer, bécause the lotus and cat-tail grew inter- 
mingled in several places (Pl. [1V, A). In attempts to find where the 
larvee went for the winter, practically every cat-tail plant in the 
vicinity of the pond was thoroughly dissected and examined. With 
the single exception of one larva found behind a leaf sheaf no trace 
of attacks on this plant were found. - 
In confinement in the laboratory partly grown larve, taken on 
lotus, fed readily and completed their growth on leaves of smart- 
weed (Polygonum pennsylvanicum), buckwheat (fLagopyrum fago- 
pyrum), and dock (Rumex crispus). In other series, larve were 
reared from egg to adult on the same plants but the authors have 
never seen any indication that these plants are used as food by this 
insect under natural conditions. Numerous aquatic and subaquatic 
plants and a large number of the common wild plants and weeds 
were offered to the larve, but all were refused except those men- 
tioned. It is noteworthy that the normal food plants of P. ainsliet 
are Polygonaceae but that that species can not develop on lotus. 
There is a suggestion here of some common ancestry for the two 
species, with members of the Polygonacee as their food plants, and 
that P. penitalis, having taken to lotus comparatively recently, has 
not entirely lost its taste for the smartweed family. 
ENEMIES. 
In the course of its life several perils threaten the safety of this 
insect. It does not seem to us that Welch’s point (74, p. 2/8), as to 
the construction of the silken web being a special adaptation to its 
anthingeg 
