Larva of tiger beetles live in burrows digged in the ground perpendicular to the surface, the depth varies greatly, depending on the type of soil and to geographic location. The entrance has no cone, becouse the larva puts the material it digs up as far away as possible. The big mandibles are used to dig the burrow and they stay at the top, waiting for small insects to pass close enough for capture.
When you find a burrow it si not easy to see the larva becouse it has seen you arrive and goes to the bottom, but if you wait a bit you see it come up. They are very sensitive to vibration of the ground. The entrance not always is open becouse the larva closes it before molting, during pupation, aestivation, hibernation and other things, like after eating, in rainy days and other conditions that makes it feel safe.
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