Classification: | Kingdom: Animalia | Phylum: Arthropoda | Class: Insecta | Order: Hymenoptera | Family: Sphecidae | Genus: Chalybion |

In December 2014, a group of wasps started to use my home as their resting place for the night. The group settled in around 6 to 7 pm on the inflorescence of a sedge (Fimbristylis dichotoma) that grew from a pot at my balcony and check out in the early part of the morning.

In the book titled "Sphecid wasps of the World, a generic revision" published in 1976 (page 102), it noted that Chalybion species commonly forms "sleeping" aggregations. This particular "sleeping" aggregation had around 2 to 5 members.

It looks very similar to Chalybion japonicum. While those above were found in my home, the one below was seen in the forest.