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Entomology (Study of Bugs)/Gnat-sized caterpillar clusters on stucco


stucco larvae015
stucco larvae015  
Hi Ed,

Periodically I notice these irregular spots, about 2" x 1.5" on the exterior stucco of my 85 yr-old home in Oakland, CA. On closer examination the clumps are composed of a single layer of tiny, caterpillar-like insects that are covered with many fine hairs. They hang there, not moving. When I picked up a few, some of them were connected by a gossamer filament.

I scanned the critters at a high resolution - the scan is attached.
Do you have any idea what they are - or what they will become?

Thank you!


Dear Alison - At this very early stage of development, it is very difficult to say exactly what these are other than newly hatched moth larvae. I suspect that they will prove to be either in the family Lasiocampidae or Lymantriidae - see for an example. I can only suggest that you keep an eye on them, and see if you can obtain a sharp image of one or more of them at a later stage of development.

Hope this helps,

Entomology (Study of Bugs)

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Ed Saugstad


Will accept most questions in general entomology, including those related to medical entomology, taxonomy, ecology, arthropod surveillance, and pest management. If you are requesting a 'mystery bug' identification, PLEASE either attach an image to your question, or post an image on a web page (such as Flickr) so that I can look at it, as verbal descriptions frequently are insufficient for a definitive identification.


21 years in the U.S. Army as a medical entomologist; duties varied from surveillance of pest populations (including mosquitoes, cockroaches, ticks, and stored products pests) to conducting research on mosquito-virus ecological relationships and mosquito faunal studies. Ten years as a civilian analyst for the Department of Defense, primarily on distribution of vector-borne diseases worldwide. Limited experience on surveillance of agricultural insects in North Dakota and Indiana.

Entomological Society of America, West Virginia Entomological Society, Society for Vector Ecology, National Speleological Society, West Virginia Association for Cave Studies.

American Journal of Public Health, Contributions of the American Entomological Institute, Japanese Journal of Sanitary Zoology, Journal of Economic Entomology, Mosquito News, and Mosquito Systematics.

B.S. in entomology from North Dakota State University in 1963, M.S. in entomology from Purdue University in 1967.

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