Observation notes: Observed this caterpillar first around 8 July 2019 when it was a mere 1/2 inch in length. At this point, it is now 1 1/2" in length. Have been watching it as it consistently has resided in a small Japanese Maple tree in my landscaping. In the extreme heat (temps or heat index over 95), caterpillar goes into hiding. Appears to enjoy being lightly sprayed with water. Have been careful not to touch this caterpillar; I understand it may be extremely venomous.