Emergence Failure

Molting, or ecdysis, is a dangerous time for any insect. Before molting, in insect must find a secure perch where it will remain until is completes the process.  Molting insects must split their skins, which also serve as their skeletons. Then, they must use what are effectively hydraulic movements to pull their bodies out of their old skins and expand their entire bodies, including delicate structures such as wings; sometimes this process involves significant changes to the insect’s general shape. During this process, the insect is soft, vulnerable, and unable to make normal movements. Once the new skeleton has hardened, the insect cannot change its shape.  Molting can fail at any stage.

Failed emergence
The cicada in this photograph failed to emerge completely from its nymphal skin. It hardened and died partially emerged.

Cicadas sometimes fail to properly inflate their wings after molting; such individuals can be found in low vegetation in any emergence.

Failed wing expansion
The cicadas in this photograph completed their molts, but they failed to properly expand their wings before hardening.
Male crumpled wings
This male cicada with improperly expanded wings cannot fly, but it still calls and walks around the chorus.

The reasons for molting failure are unknown.  Possible explanations include crowding (since many molting insects in a small space may knock each other down), disturbance (such as winds or storms that knock molting insects from their perches),  and pesticide or lawn chemical use.