TACIIINIl) PAKASITK OF liEE. , 190 



striking" at a number of bees (up to a dozen or more) in this 

 wa3', the i\y settles down for a few moments rest, after which 

 the above tactics are repeated once more. 



Each time tlie fly touches one of tlie incoming- worker 

 bees she deposits a tiny larva on its body, and this larva 

 burrows into the abdomen of its host through the interseg- 

 mental membranes. It is difficult to catch one of the stricken 

 bees before it enters the hive, although it can be done at the 

 expense of much patience and several stings. The manner 

 in which the larva enters its 'host can be easily observed, 

 however, by catching one of the females and a few bees and 

 stupefying them with chloroform. The larvae can then be 

 dissected out of the fly and placed on the bees' bodies by means 

 of a damp camel-liair brush. The manner in which these 

 larvae crawl about until they reacdi the joints bet^^'een the 

 abdominal segments can then be readily observed with a strong- 

 lens. At this stage the larvae are half a millimetre in length, 

 and marked with numerous broken, shallow, longitudinal 

 creases in the chitin (Fig. 5). 



The parasite feeds on the abdominal tissues of its host, 

 but seems to leave the .alimentarj- canal and the nervous 

 system to the last, for I have caught bees flying vigorously 

 around tJie hives Avliich on dissection were found to contain 

 full-grown larvae occupy iiig almost tlie whole of the abdomen. 

 On no occasion have I found these parasites in the head or 

 thorax of their hosts. The deatli of a i)ai-asitised bee is very 

 sudden. Twice I have been fortunate enough to see a flying- 

 bee fall suddenly to the ground and die in a few minutes, 

 and about ton minutes afterwards a full-grown maggot has 

 forced its way out between the abdominal segments of the 

 dead body of its host. 



The larva when fully grown measures about eight milli- 

 metres in lengtli, and can be easily recognised by the two 

 large circular black spiracular plates at the posterior end of 

 its body (Fig. 2). Xo orifices are discernible in these plates 

 even under tlie microscope after boiling in potash. The bticcal 

 armature is shown as viewed from above in Fig. 2, and from 

 the side in Fig. 5. 



After leaving the dead body of the host, the larva may 

 either bui-rf)w into the ground or it may seek out a sheltered 

 spot beneath dead leaves, stones, etc. A number of them were 

 caught by the simple expedient of placing pieces of board 

 on the ground around the hives. The larvae that had left the 

 bees that had died in or near the hives crawled under these 

 boards to pupate. The puparium is formed very rapidly, 

 within half an hour of leaving tlie host, and the dark brown 

 colour is assumed within an hour. They are oval in shape, 

 blackish-brown in colour, about six millimetres in length, and 

 may be recognised by the conspicuous circular sjjiracular 

 plates. 



I have found these i)uparia buried aboTit an inch beneath 

 the soil where the ground was loose, beneath dead leaves, 

 under stones, under the legs sui)porting tlie hives, and also 



