INTESTINAL MY1ASIS 203 



nose, if there be one, and travel rapidly to conceal them- 

 selves in any dark recess under the mattress, in the frame- 

 work of the bedstead, in cracks in the floor or wall, or 

 in any old clothing that may be lying near. A thorough 

 and careful search should always be made for. the larvae 

 and on subsequent days for the pupae. They conceal 

 themselves in such small crannies that some usually 

 escape detection and a few freshly emerged imagines 

 will generally be found in the vicinity of the bed (fig. 78) 

 on the early morning of the ninth day after the escape of 

 the larvae in a tropical climate such as British Guiana. 



The Chrysomyia macellaria is a fly that varies in colour 

 from blue to green. It can easily be distinguished from 

 Lucilia as there are broad black bands running length- 

 wise on the thorax (fig. 78). Badly kept hospital wards, 

 such as those in an undermanned leper asylum, are very 

 liable to become infected by previous cases, as the pupae 

 are not looked for and are allowed to hatch out, when 

 they may reinfect other patients. In Asia, a fly a 

 Pyonosotna, sp. (?) similarly attacks the nostrils, and may 

 cause death. They are not so common as Chrysomyia 

 are in Tropical America, and in appearance, without 

 close investigation, resemble that insect. Some observa- 

 tions show that other flies may act in a similar manner, 

 including Sarcophaga. 



INTESTINAL MYIASIS. 



Intestinal myiasis occurs in temperate climates, as well 

 as in tropical ones. Some of the cases reported are prob- 

 ably mistakes, as flies that deposit living larvae do so so 

 rapidly that they are deposited on the faeces as they are 

 passed through the anus. Amongst the flies that so 

 deposit larvae are several species of Sarcophaga, and in 

 some of the recorded cases of intestinal myiasis the larvae 

 were those of Sarcophaga. 



Undoubted cases do occur in which well- developed 

 larvae are passed with the faeces. The larvae are some- 

 times those of Anthomyidae, e.g. Anthomyia desjardensis. 



