Smerinthus ophthalmica Eggs Pharate

Our Smerinthus ophthalmica eggs have become pharate and are about to hatch. This stock originated locally here in Albany, California.

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Our 11 day old Smerinthus ophthalmica eggs are pharate and are about to hatch. The eggshell is completely translucent now, revealing the larva inside. The larva's body is curled up into a two loop spiral; the first part is the head, thorax and upper abdomen, and the second part is the lower abdomen which bears the prolegs and horn. From observing the changes over the days, it is now clear that the milky white edges with a brown ring that was previously present has become the abdomen -  you can see now that the brown has diluted into a pinkish color along the center of the dorsal abdomen of the larva. The yellowish center before has now become the second loop in the spiral, the lower abdomen. 

When examined very closely, it is possible to see all the larval structures within the egg in great detail. Some of the large, obvious structures are the head (the greyish round portion), abdomen (the yellowish white and pink portions), and horn (the orangish tail-like structure). If you look a little closer on the head, you can see a few small spots that are the eyes (obvious on the eggs third, fourth, and fifth from the left), as well as the mandibles (obvious on the egg fourth from the left) and cleavage line (obvious on the egg fifth from the left). Looking extremely closely on the ventral abdomen, you can see a row of four slightly darker patches which are the prolegs. 

Since the eggs are pharate (the larva inside is fully developed and is waiting for the right time of day to hatch), you can actually observe larval movement inside egg. Below are two close-ups shots of the eggs taken a second after another, and if you focus the on the one in the center, you can see that the larva inside has moved as it is in a slightly different position in the two photos. In the first photo, the horn is slightly more curled and the head is fully exposed, but in the second photo, the horn is more relaxed and the larva has moved its abdomen to cover its head.

The pharate eggs of this species are truly amazing to look at as it is very interesting to see the larval structures inside. These eggs are so close to hatching that they should definitely hatch tomorrow morning. 

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Authors
Alan Liang

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