120 PROCEEDINGS ENTOMOLOGICAL SOCIETY 



harbor the large predaceous bug, Harpactor iracundus, which 

 commonly hunts the workers of A pis mellifica. The pollen and 

 sweet juices covering its body attract many Desmometopa 

 m-nigrum. As long as Harpactor lies in wait, no flies appeared ; but 

 as soon as the table was set, they immediately gathered about. 

 It appeared to be their determination to feast only in the pres- 

 ence of the hunter, for when I had removed the Harpactor I of- 

 fered them the body of the bee in vain; none came to it. But 

 I succeeded in deceiving them by placing beside the bee the 

 killed bug. Furthermore, they must have a good sense of smell, 

 for a dried Harpactor, or one killed some hours previously, failed 

 to attract them. 



"At Singapore I met with Desmametopa flies again in April 

 of this year. One night I collected a nest of Apis florea Fab., 

 var. andreniformis Sm. with its entire inhabitants, and from the 

 following noon on single small flies came flying to the dead bees 

 and the cells laid out to dry. They were easily recognizable by 

 the M-shaped mark on the frons and in their movements and 

 manner of flight behaved entirely like their European relatives." 1 



This last observation induced Biro to incline to the belief that 

 the European Desmometopa also might be attracted, if a large 

 quantity of dead bees and comb were suitably exposed. Still 

 another observation made by Biro in Singapore is quoted by 

 Kertesz in connection with the original description of Desmometopa 

 singaporensis. 2 According to Biro's note, this species u lives in 

 the same manner as the European species and appears at once 

 when a spider or Harpactor kills a bee." 



More recently Dr. Carl Lundstrom, in Sweden, confirmed a 

 part of Biro's statements by independent observation. "On 

 June 17 of last summer (1905) I observed a swarm of from 20 to 

 40 small black flies flying about on the flower-heads of a bush 

 of Cornus alba in the garden of Julia in Kunsto. By close obser- 

 vation I saw that it was not the flowers that attracted the flies, 

 but a recently killed bee which a spider was clasping around the 

 head and sucking. Unceasingly some of the small flies alighted 

 upon the abdomen of the bee, stayed there for a moment, and 

 then flew up to rejoin the swarm and make room for others of 

 the flies; but during the whole time the swarm itself remained 

 in the same position, flying around the bee." 



Lundstrom caught some of the flies, and of six specimens pre- 



1 Biro, Ludwig. Asztalkozosseg a legyeknel. Commensalismus bci 

 Fliegen. Termesz. Fxizetek, vol. 22, p. 190-199, 200-204. 1899. 



2 Kertesz, Koloman. Verzeichniss einiger von L. Bir6 in Neil-Guinea 

 und am Malayischen Archipel gesammelten Diptcrcn. Termesz. Fiizetek, 

 vol. 22, p. 173-195 (Bir6 quoted, p. 195). 1899. 



