26 MISC. PUBLICATION 631, U. S. DEPT. OF AGRICULTURE 



Larvae should be removed with as little injury as possible and, as 

 a rule, handled no more than necessary. If practicable, it is best to 

 remove them with a forceps from the wound before any antiseptic has 

 been applied. If an antiseptic has been used, they should be washed 

 quickly in normal salt solution. 



Rearing procedure depends largely on the habits of the parasite. In 

 general, it is much more difficult to rear obligate parasites than faculta- 

 tive ones. Of the facultative parasites, breeding of the carrion feeders 

 requires precaution against contamination of the culture medium by 

 other species. There is always some danger that meat obtained from 

 stores has been previously blown; moreover, breeding conditions 

 should be such as to guard against a subsequent blowing. To cover 

 the breeding medium with cheesecloth or gauze, even if double-layered, 

 is not always sufficient. It is well known, for instance, that females 

 of some species of Sarcophaga will drop their larvae through gauze 

 or netting, or place them where they can crawl through the material. 

 Patton (102) says that in India glass jars covered with glass lids, 

 the edges of which were carefully vaselined, were not adequate to 

 prevent contamination. 



Directions given here are only complete enough for the rearing of 

 partly developed larvae to the adult stage. If it is desired to rear 

 successive generations of any of these flies, the original sources cited 

 should be consulted. 



SPECIFIC MYIASIS PRODUCERS 



Specific producers of myiasis, being obligate parasites, are unable, 

 as a rule, to live on any medium other than the tissues of a living 

 animal. The various warble flies and botflies (Oestridae, Gastero- 

 philidae, Hypodermatidae, and Cuterebridae) remain attached to their 

 hosts until ready to pupate ; if artificially removed they will die, be- 

 cause they are still immature. Such larvae should therefore be pre- 

 served in alcohol, as it is useless to try to rear them. Mature larvae 

 that have left their host will pupate if transferred to a box containing 

 some damp earth. On the other hand, some Calliphoridae and Sar- 

 cophagidae, even though obligate parasites, can be reared to maturity 

 from partially developed larvae. 



Wound-infesting species. — Patton (101) has succeeded in rearing 

 Chrysomya bezziana by transferring the larvae to wounds in experi- 

 mental animals, and Melvin (Galtsoff and coworkers ^ p. 1±1%, J±13) 

 recommends a similar technique for Callitroga americana and Sar- 

 cophaga bullata. Melvin, using rabbits, placed the larvae in a wound 

 made by cutting with the scissors a plug 1 inch in diameter out of a 

 fold of skin in the rump ; the wound was then covered with a piece 

 of moist cotton held in place by adhesive tape, and the rabbit kept 

 in a cage 20 inches long by 4% inches wide. The width of the cage 

 is important ; it should be narrow enough to prevent the rabbit from 

 getting its head to the wound to destroy the larvae. 



To rear third- or even second-stage larvae of species other than 

 Chrysomya bezziana, however, various workers have shown that a 

 living host is not necessary. Callitroga americana larvae can ma- 

 ture on fresh rabbit or guinea pig carcasses at a temperature of 

 about 90° F., and newly hatched larvae produce at least a small per- 

 centage of undersized, though otherwise normal, adults on fresh lean 



