In the spring of 2011 observations are made on the Chrysidid wasp Chrysis angustula parasitizing a nest of Symmorphus bifasciatus. Also development of the larvae is observed. I found that the egg was placed in the breeding chamber the moment that the female of Symmorphus had almost finished closing the breeding chamber with mud. For the breeding chamber see figure 1. It shows the egg of Symmorphus whitch is put there first, than the paralysed larvae of Chrysomela and final the egg of Chrysis angustula. After about 48 hours the egg of the Chrysis hatched and the larvae crawled slowly to the egg of Symmorphus and start to eat it. This took about 24 hours then the Chrysidid larvae started to eat the Chrysomela larvae. After nine days al the food was eaten. After defecation the larvae started spinning a cocoon. After overwintering the cocoon in an artificial nest (figure 2 right) a female Chrisidid was born on the 21 of April 2012.