If not tomorrow, then I expect the monarch butterfly to hatch Thursday morning at latest. He'll be a crumpled thing with tiny wings and he will need to hang upside down and flap for a couple of hours to get the juices out of his swollen abdomen and into his wings.
They take 10-14 days to hatch, and cooler weather and being a last generation monarch pushes it to the longer side of the gestation. The last generation of monarchs are those born in late August/September, like this guy. The first 3 or 4 batches of monarchs hatched between March and late summer last only a couple of weeks to mate, lay eggs, and then die. But the fall brood could last 6 to 9 months because they fly south for the winter to hang out in Mexico in a particular fir tree, if they are east of the Rockies. A few make it to the Caribbean. Monarchs west of the Rockies go to hang out in eucalyptus trees along the southern California coast. Then they all head north in March or April to do the mate and die thing because the milkweed that the caterpillars eat doesn't grow down where the butterflies hang out for the winter.
This has been your Wednesday Bio Factoid.
I'm so sorry I'm so behind in replying to comments. Time keeps running out on me and I figure you'd rather me post things and comment on your entries first, so I'm doing that and hope to get back to replying as I can.
Also posted at http://lavendertook.dreamwidth.org/120379.html with comments