University of Kentucky Department of Entomology

Mystery Bug Answers

Mystery Picture #30

Mystery Picture #30

(Mystery Pictures)(Mystery Pictures)


This object is not actually an insect but the egg case of the Praying Mantid, a beneficial insect. After mating, the female praying mantid will lay a group of 12-400 eggs in a frothy liquid that turns to a hard protective shell. This is how these insects survive the winter. When the young insects emerge in the spring, often their first meal is a sibling!

Praying mantids are very interesting insects. Some of you may remember that the adult insect was featured as a one of our first mystery bugs. To learn more about them, see EntFact 418 - Praying Mantids.


This robust Blue Bottle Fly, one of a group called blow flies, has a shiny metallic body and can often be found in homes during winter and early spring. The blue bottle fly develops in manure or carrion and is usually apparent in small numbers. However, it is a strong flier and is attracted to lamps or lights. Its "buzzing" flight is very annoying.

Annoying is not the word! One of these flies was flying around my house a while ago and my dog, who was stung by a bee once and now is terrified of anything that buzzes, took off in a mad dash around the living room trying to escape. I grabbed a newspaper to swat the fly and, under some pressure to get it quickly before ALL the furniture was destroyed by the dog, jumped up on the couch and armchair,all the while flailing mightily. The cat came in to see what all the commotion was about, saw the fly, and also began leaping wildly from bookcase to couch to chair trying to catch it. I imagine to anyone passing by outside, we must have looked like a room full of Mexican jumping beans! (Merry Christmas! Happy Holidays! PD)

For other control options that are not so hard on the furniture, see EntFact 624 - Cluster Flies, Face Flies and Blow Flies in Homes.

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