62 ENTOMOLOGICAL SOCIETY 



One afternoon about 4 o'clock a heavy thunderstorm came 

 up from the west accompanied by much rain. When the 

 storm passed by, about an hour before sunset, it was fol- 

 lowed by large numbers of birds of many species, but mainly 

 the smaller insectivorous birds, warblers, etc. They were 

 moving in the direction the storm had taken and were evidently 

 feeding as they went, though passing quite rapidly. Accom- 

 panying them was a number of Cuban nighthawks flying 

 rather'low at about the level of the tops of the somewhat low 

 trees fringing the coast at this point, or, in other words, at a 

 height of 25 or 30 feet. 



Two of these were taken and on preparing the skins were 

 found to be exceedingly fat while the stomachs were distended 

 with mosquitoes, apparently a small species of Culex and re- 

 sembling the species that was most abundant in the locality. 



The stomachs of a few warblers taken at the time were 

 also full of mosquitoes. Unfortunately I made no note of 

 stomach contents of other specimens of the species taken at 

 other times and points in the island. 



Mr. Schwarz exhibited a photograph of the tubes of a 

 common blue mud dauber from Plummers Island, Maryland, 

 probably Chalybion ccendeum L. He said that there were 

 various facts in the life history of the insect which were un- 

 known to him ; for instance, how many tubes are built by a 

 single female ; how the hissing noise made by the female while 

 constructing cells is caused ; whether the tachina fly, Pachy- 

 ophthalmus signatus Meig., which is reared from the tubes is 

 parasitic upon the wasp, on the spiders, or on the insects that 

 form its food, and how the fly emerges from the hard clay 

 tube. 



Mr. Schwarz gave an interesting account of an observation 

 made by various members of the Washington Biologists' Field 

 Club last summer, of the manner in which one tachina fly 

 tried to enter one of the mud dauber tubes and how the parent 

 wasp defended its home against the intruder. 



Doctor Howard said that all of the European records giv- 

 ing parasites of the mud daubers were wrong. In every case 

 the parasite was upon the insects carried in as food instead of 

 upon the wasp itself. 



