AN ISLAND SETTLEMENT. 69 



No. 44. August 10, 3 P. M. Opened nest and found a half grown 

 wasp larva and five larvae of parasitic flies, all eating. The fly larvae 

 were very lively and were two-thirds as large as the other. They 

 were surrounded by the remains of large numbers of flies. We gave 

 the wasp larva seven house-flies. 



August 11, 8 A. M. The larva has eaten all the flies put in yester- 

 day. We now give it six house-flies and the large Tabanus taken at 

 the colony. 



August 12, 5 P. M. The flies are all eaten. The larva is very large. 

 We now give it ten house-flies. 



August 13, 9 A. M. The flies are not quite gone but we give it eight 

 more. 



August 14. The larva has eaten all the flies. We give it six more. 



August 15, 8 A. M. We give the larva eight flies. 5 P. M. The 

 larva has left three flies uneaten and has begun to spin its cocoon. 

 In five days it has eaten forty-two flies besides the big Tabanus. 



No. 46. August 10. We saw spinolae take a fly into the nest. After 

 a short time we opened the nest and found the fly with an egg attached 

 to the left side of the thorax just at the base of the third leg. It was 

 long and cylindrical. The fly belonged to the genus Syrphus. 



August 13. The egg is evidently dead. 



No. 54. We opened a nest and found a larva two-thirds grown, 

 three active maggots, and the remains of flies. 



No. 55. On August 10, 3:45 P. M. We saw a nest made and a fly 

 taken in. We opened it today, August 16. Assuming that the egg 

 was laid on the first day, we judge that it hatched in two days, since 

 the larva seemed to be about four days old. We found no maggot in 

 this nest, and not many remains of flies. 



Mr. Hudson gives an account of a common La Plata species 

 of this family that has the same habits.* This wasp, Monedula 

 punctata, digs her hole and lays therein a single egg. When 

 the grub hatches the parent keeps it bountifully supplied with 

 insects since it is sometimes surrounded by an accumulation of 

 six or seven which are still untouched. The prey taken con- 

 sists to some extent of fire-flies and other insects, but flies are 

 always preferred. The nest is always closed by the wasp be- 

 fore she leaves it, to protect it, Mr. Hudson thinks, from hunt- 

 ing-spiders, ants, and tiger-beetles. No mention is made of 



*Naturalist in La Plata, p. 162. 



