PSYCHE. 
frequently found them when they were 
not feeding, but they were either molting, 
sick, parasitized or alarmed. 
The cocoon of this species is slightly 
reniform, about 2 mm. long and of a 
bright golden yellow. The larval life 
does not exceed eight days in the mine, 
and is therefore half as long as that of 
NV. pteliaeella, anew species of which 
the imago is yet unknown. Its food 
plant, Ptelia trifoliata, called also ‘‘ Hop 
bush,” or ‘‘ Bush clover.” is by no means 
abundant in this locality (Covington, 
Kentucky), at least I have but seldom 
met with it; but where I have found it 
in August, every leaf is always mined by 
the larvae of this species, and many 
leaves have as many as forty larvae in 
each. The larva is bright green, the 
intestine being filled with blue-green pel- 
lets looking sometimes almost like indigo. 
It undergoes two molts while still in the 
mine, besides that in the cocoon by which 
the pupa is disclosed. Abundant as are 
the mines, I have never seen the egg even 
on the youngest mines. It seems to be- 
come soon detached from the leaf and 
lost. The mine is at first an oval or ir- 
regularly roundish blotch about 2 mm. in 
diameter, made by eating out the paren- 
chyma around the spot at which the larva 
enters the leaf and the entire parenchyma 
is eaten out. About three days are con- 
sumed in making this part of the mine, 
but as it was already begun in each in- 
stance I cannot be more exact as to the 
time. The larva is now 0.8 mm. long; 
it ceases to feed and undergoes its first 
molt. This occupies not less than forty- 
eight hours; I cannot be more exact 
because in every instance the molt was 
either begun or ended in the night. The 
137 
molt accomplished, it begins to feed 
again, leaving its little blotch and making 
an exceedingly serpentine or zigzag track, 
packed densely with little green pellets 
of frass placed transversely. The mine 
is linear and no wider than the body of 
the larva; the parenchyma next to the 
under surface is not eaten; and if the 
larva happens to strike a vein in its course 
the mine ceases to be crooked, and passes 
straight along the vein. This part of the 
mine is very distinct from that of the first 
stage, is about 25 mm. long, and it takes 
the larva three days to make it. Feeding 
then ceases, and forty-eight hours are 
consumed in the second molt, which being 
finished, feeding begins again. At the 
beginning of this molt the larva is 1.6 
mm. long, having just doubled its length 
since the first molt. The mine of the 
third stage is similar to that of the second, 
though readily distinguishable from it by 
being a little wider, and having the trans- 
verse rows of frass not so densely packed 
—a little wider apart—and the frass black 
instead of green, and in the last part of 
it (for 12 mm. before the end) it is placed 
in a central line, and not in transverse 
rows. ‘This part of the mine is so crook- 
ed that it is impossible to give its length 
accurately, but it is more than 75 mm. 
long, and that of the whole mine is not 
far from 110 mm., or twice as great as 
that of N. fuscotibiaeella. No molt 
occurs in this part of the mine, which is 
made in six days, equal to the other two 
stages combined, and making the larval 
life in the mine sixteen days — about twice 
that of WN. fuscotibiaeella. 'The length 
of the larva at the end of this stage is 3.2 
mm., just twice what it was at the second 
molt. (To be continued on p. 147.) 
