160 



Psyche 



[December 



A NOTE ON THE HABITS OF EPACTIOTHYNNUS 

 OPACIVENTRIS TURNER, AN AUSTRALIAN THYN- 

 NID WASP. 



By Francis X. Williams, 

 Hawaiian Sugar Planter's Experiment Station, Honolulu. 



During the winter of 1919, while engaged in entomological work 

 on the Herbert River, North Queensland, for the Experiment 

 Station of the Hawaiian Sugar Planter's Association, I made a 

 few observations on this wasp. Epactiothynnns opacirentris is a 

 moderately small species of the great Australian group of Thyn- 

 nidse. The male measures about 11 and the female 8 mm. in 

 length. At the time of observation it was the most abundant of 

 the few species of Thynnids then flying and its main food flower 

 was Crotalaria sp., a common weed along roadsides and edges of 

 fields. 



I can find nothing in literature which relates to the egg and 

 larval stages of any of the Australian Thynnidse, though Froggatt 

 (Australian Insects, 1907) has dug up cocoons which yielded a 

 large species. He states that these wasps probably parasitize the 

 larvse of Lamellicorn beetles. 



When females of Epactiothynmis were enclosed in a tumbler or 

 shallow dish of soil with Lamellicorn grubs about 14 mm. long, 

 and which were common in some of the cane fields, these grubs 



Fig. 1. Larva of one of the Scarabseid beetles, showing egg of Epactiothynnus 

 opaciventris on its mid-ventral line. (X 4.25, North Queensland.) 



