The blotched emerald (Comibaena bajularia) is a moth of the family Geometridae.

In the southern part of the British Isles it flies in June and July, where it may be common in some oakwoods.

The body of the caterpillar larva is red brown, but it camouflages itself by attaching a screen of oak leaf fragments to its specially hooked bristles.

After overwintering, the attached camouflage changes and consists of bud scales from the oak tree.

Hugh Cott compared the larva's use of "concealment afforded by masks of adventitious material" to military camouflage, pointing out that the "device is, of course, essentially the same as one widely practised during World War I for the concealment, not of caterpillars, but of caterpillar-tractors, [gun] battery positions, observation posts and so forth.