1919] 



Williams — Habits of Epacliothynnus opaciventris Turner 



161 



were eventually stung to almost complete paralysis, just as the 

 Scolias sting their prey. I did not observe the act of stinging, but 

 a single Epactiothyunns would sometimes paralyze several grubs 

 overnight. Something was wrong, however, perhaps the weather 

 was too cool, for of the many grubs stung but one had an egg 

 upon it, and that failed to hatch. The egg (Fig. 1) is deposited 

 along the mid-ventral line of the larva. It is pearly white, 

 somewhat arcuate, thicker at one extremity, and measures 1.85 x 

 0.40 mm. 



Tachynomyia sp., a darker and somewhat larger Thynnid was 

 found also to paralyze the same species of beetle larva that was 

 offered to Epactiothynnus. 



In the bulk of the Thynnidse the strong-winged male, as he 

 flies from place to place or feeds at flowers, carries his apterous 



and obese partner with him. In cap- 

 tivity, at least, two Epactiothynnus 

 may remain paired for several days. 



Fig. 2 is a drawing from life of a 

 small species of Thynnid taken near 

 Sydney. She was first observed crawl- 

 ing on the ground, then ascend a reed, 

 place herself in an inverted position, 

 with the abdomen inclined a little for- 

 ward, and thus motionless to await the 

 coming of the male. Epactiothynnus 

 females had the same habit awaiting 

 their mates in a conspicuous place. 

 The circling males sometimes betrayed 

 her whereabouts; as soon as located she 

 was immediately seized and carried 

 off. 



Australia has perhaps the richest 

 fauna of Scarabeid beetles in the 

 world, so it is not surprising that the 

 enemies of these often destructive in- 

 sects are similarly numerous. The 

 immense Thynnid population of sev- 

 eral hundred species far outnumbers 

 the Scoliidse, and it may be affirmed 



Fig. 2. Female Thynnid on 

 reed; in such a position, she 

 awaits the advent of the winged 

 male, which carries her off. 

 (X 6.7, Sydney.) 



