NOTES ON THE MYIASIS-PRODUCING DIPTERA. 259 



I will now suppose a medical or veterinary officer has a case of myiasis, and wishes 

 to know how best to set about rearing the larvae, breeding out the flies and identifying 

 at least the genus to which the larva belongs. If the case is one of dermal or subdermal 

 myiasis, for instance a cut, sore or wound on the human body or that of an animal, 

 there should be no diificulty in obtaining a number of living larvae. It is sometimes 

 quite easy to extract the larvae without injuring them, but in the case of Chrysomyia 

 hezziana the strongly developed, backwardly directed spines catch in the tissues, 

 and, as often as not, the larva is torn in half, and then is only of use for purposes of 

 identification. It is best to apply a small quantity of glycerine or very dilute chloro- 

 form water to the area where the larvae are, and then some will emerge, or so alter 

 their positions that they can be extracted without damage. It is very probable that 

 the larvae are all at the same stage, though there may be more than one species 

 present. As many as can be removed alive should be placed in a tube, and one or more 

 then dropped into boiling water in order to stretch them out and render examination 

 more easy. The truncated end should be examined with a hand lens, and if the 

 posterior stigmata are small and there are only two slits the larva is a second-stage 

 one. A few should now be preserved in 80 per cent; alcohol, after killing them by 

 dropping them into boiling water or hot 70 per cent, alcohol, and a label with details 

 written in pencil put in the tube, which should be well corked. It is now necessary 

 to rear the remaining living larvae, and this is best accomplished by placing them on 

 a piece of meat, or in the mouth of a dead bird or small animal. Those who have 

 not reared any of the larvae of the myiasis-producing Diptera may be misled by 

 thinking that this part of the investigation is quite easy, but I would like to warn 

 them that this is by no means the case; indeed it is by far the most difficult part of 

 such an inquiry. In the Tropics great care has to be taken to prevent other blowflies, 

 and particularly species oiSarcophaga. from laying their eggs or depositing their larvae, 

 as the case may be, in the meat or the body as soon as it begins to decompose. I 

 have tried every kind of receptacle in which the meat, etc., was placed, and have even 

 sealed the lid with vaseline, but in every case the larvae of other blowflies, and 

 especially Sarcophaga, have made their way in, and then the special larvae removed 

 from the case of myiasis have soon disappeared. Fabre long ago suggested that a 

 paper bag was the best way to prevent blowflies from laying their eggs in meat ; 

 and taking advantage of this suggestion I placed the meat containing the larvae to be 

 reared in several sheets of newspaper, turning down the ends and tying it up into 

 a packet. No larvae can now find their way into the packet, provided that the 

 moisture which exudes from the decomposing meat or body does not soak right 

 through, and forming a wet patch under the packet, so soften the paper as to aflow 

 small larvae to eat their way in and reach the meat. As soon as the outer part 

 becomes wet, the packet should be wrapped up in several fresh sheets of newspaper ; 

 and this may have to be repeated several times. Although large numbers of 

 eggs may be laid under the packet, as long as the outer layers are dry the larvae 

 cannot make their way to the meat. When the special larvae are nearing maturity, 

 they crawl out into the folds of the paper and pupate, so that it is necessary to examine 

 the packet for such larvae every two or three days ; larvae about to pupate can 

 always be recognised by their yellowish- white colour and the absence of food in 

 their alimentary tracts. Several mature larvae should be preserved, as noted above, 

 the remainder allowed to pupate, and the puparia later removed and placed in tubes 

 with well-fitting corks. From 24 to 36 hours after the flies have hatched they should 

 be killed and pinned with their empty puparia ; and all dead larvae, whether first, 

 second or third stage, preserved in one tube containing 80 per cent, alcohol. 



I have collected most of the Indian Calliphorinae and their early stages by 

 placing dead animals out in the open, and when a female of any species came to lay 

 its eggs, it was carefully observed, and after a large number of eggs had been laid, in 

 most instances the fly was caught, pinned and identified. The mass of eggs was then 

 removed by cutting off a piece of tissue, so as not to injure the eggs ; a few were then 



