—13— 
always found two eggs; the first at the upper extremity, and fastened by 
some adhesive substance on the egg itself. Back of this egg, a piece of 
pith seems to be shoved in, to aid in holding it in place, and to hold it 
from the second egg, which is placed directly behind this, and frequently, 
but not always, a piece of pith is placed behind the latter also. While it 
“might be too much to say that the invariable number of eggs is two, in 
each chamber, and that there are always two chambers connected with 
each channel, with a single exception we have found this to be the case. 
In the exceptional case, there was a channel fully twice the ordinary 
length, and four chambers connected with it ; the second and third, how- 
ever, being much more distantly placed than the first from the second, or 
the third from the fourth. Just why so much method should be followed 
in this arrangement, it is difficult to understand. Possibly the female 
may comprehend that were she to place herself in a reverse position on 
the plant, the chambers would extend downward and a drop of water or 
dew, on its way downward on the outside of the stem, might penetrate 
the latter and destroy the eggs, the young larve, or even the entire plant. 
As it is, the chamber extends upward, and, besides, the gum, which 
exudes from the plant, collects in the mass of fibres in the channel, and 
as this gum hardens it tends to seal the whole entrance. The secret of 
the number of egg chambers, per each channel, may lie in that the latter 
is as Jong as the female can make it without changing her position, as, 
with the weight of the male added to her own, moving about would prove 
too laborious. With two eggs in each chamber, there need be no con- 
flict among the young larva, as one can work upward and the other 
downward ; the only chance for a conflict here being, that the lower one 
of the upper chamber might come in contact with the uppermost larvae 
of the lower chamber. ‘They are certainly not quarrelsome, however, as 
we have taken thirteen full grown larve from a section of Helianthus 
only about as many inches in length. 
The egg of Zzvus concavus is oblong-oval, smooth, of a very light 
yellow color, 1.5 mm. long, and 1 mm. in diameter. 
As to the time required for these eggs to hatch, after being deposited, 
I have no exact data, but think Mr. Coquillett’s opinion respecting those 
of Z. macer, would apply to concavus also, as my own observations in- 
dicate that the period covers only a few days. 
In the latitude of LaFayette, Indiana, the eggs are deposited during 
July and early in August, the larvae becoming full grown by the 2oth of 
October. In the stems of the plant, these larvae are rather contracted, 
and remain, when quiet, in a somewhat curved position, being then only 
about 18 mm. in length. 
