Wednesday, June 15, 2011

Four Geometer Moths

Two nights ago I put out the black light and sheet again to attract moths. During the summer I try to do a mothing session about once per week, but sometimes the intervals are longer. This week's session was slower than last week's. The starting temperature was about 15°F cooler than the previous week, plus the moon was nearly full. Both factors may have contributed to less activity at the sheet. Still, there was a nice group of moths. I have about 10 species identified so far, with a bunch more moths left for identification.

Here are a few geometer moths that showed up. In their larval stage, Geometer moths (family Geometridae) are known as inchworms. The caterpillars lack prolegs in the middle of their bodies, so they have a looping walk, as if they are measuring the earth inch by inch. The moth above is a Single-dotted Wave (Idaea dimidiata); I had this species in the yard last summer.

Many moths have fanciful English names, such as this one, which is known as The Gem (Orthonama obstipata). In this case, the name seems deserved, given this female's rich red and black coloration. This species was new to me.

This moth is a Common Tan Wave (Pleuroprucha insulsaria).

Adult geometers usually rest with the forewings and hindwings both spread out. So I found it odd to see this moth with its wings folded over its back, in the manner of a hairstreak or blue butterfly. Unfortunately I did not get a photo of its dorsal side, so I cannot be sure of the species. If anyone wants to suggest an ID, feel free to do so.