Minutes of Proceedings. xxiii 



to the genus Bengalia. I was quite right in my surmise, the genus 

 Bengalia and Ochromyia being partly synonymous. The year 

 following Dr. Blanchard published in the Transactions of the French 

 Entomological Society, a paper on such American iEstrid flies, the 

 larvae of which live in the skin of man, and in which he dealt at 

 great length with the authenticated cases of such larvae that have 

 been found in situ or exuding from pustular sores. He concludes 

 that they are caused by iEstrid or bot flies. He stated also in his 

 ' Treatise on Medical Zoology ' that all the known cases occurring 

 in Africa were due to the iEstrid, which statement is erroneous, as 

 he himself acknowledged later on. On receipt of this publication 

 the late curator of the Museum (Mr. Trimen) caused to be sent to 

 Blanchard the invaluable two specimens we had in the collection, in 

 order that the mistake should be corrected. I had pronounced the 

 fly not to be an iEstrid at all, but a true Muscid. 



I should here mention that the family JE strides include flies 

 which are true parasites of the large mammals, and occasionally of 

 small ones, even accidentally of man himself. The perfect insect is 

 usually covered with short, dense hairs, the proboscis is entirely 

 absent, or very little developed, and the animal does not take any 

 food ; the female is provided with a long retractile oviduct. 



In the larval stage they inhabit the domesticated or wild animals, 

 and can be divided in three groups : (1) the Cuticulous iEstrids, 

 living under the skin, and often producing large tumours. I have 

 not observed any such iEstrid here on our domesticated animals, but 

 three instances of them being found on the steinbok and ouribi have 

 come under my notice ;'(2) the Gavicolous iEstrids live in the nostrils 

 and frontal sinuses, and are extremely common here. I have not 

 yet examined any sheep's head that did not contain them ; the gnu 

 and bontebok are full of them, and the hartebeest might perhaps be 

 called the sneezing antelope, on account of its pertinacity in trying 

 to get rid in that way of the numberless larvae, which, on account of, 

 perhaps, the peculiarity of the frontal bone of that animal, are said 

 to infest it more than others ; (3) the Gastricolous iEstrids, on the 

 contrary, live affixed to the internal covering of the stomach of horses, 

 cattle, and pachyderms. To this belong the well-known bot fly of 

 the horse, and according to Delegorgue,* the Rhinoceros Simus, or 

 white rhinoceros, harbours only a small number of iEstrid, while 

 those inhabiting the Rhinoceros Africanus, or black rhinoceros, might 

 be measured by the bushel. He suggests that the presence of these 

 parasites might be the cause of the irritability of that animal. The 

 iEstrids are the direct agents of the tumours in which their larvae 

 * Delegorgue, ' Voyage dans l'Afrique Australe,' vol. ii. p. 429. 



