26 THe BLOWFLIES oF NortTH AMERICA 
flames should be extinguished during the preparation or use of 
the remedy. (2) As benzol is a highly volatile liquid, and will 
evaporate quickly, it should not be left in an open container. 
When not in use it should be kept in a tightly closed container in 
a cool place. If the preparation becomes too thick through loss of 
benzol by evaporation, additional benzol may be stirred in to 
bring the mixture back to its original consistency. (3) Infested 
wounds near eyes of animals should be treated with care, for the 
preparation is irritating to the eyes. When an excessive amount 
of the mixture gets into an eye of an animal being treated, the 
eye should be washed immediately with plain water. (4) Other 
substances, such as oils or greases, may destroy the efficiency of 
the preparation and should never be added to the formula. 
Animals being treated for screwworm infestation must be 
inspected every few days and additional quantities of Formula 
62 applied until the wound is entirely healed. 
CONTROL OF OTHER BLOWELIES. The cluster fly is a 
parasite of earthworms. It occurs in dwellings only during 
winter months, coming in late in the autumn in search of hiber- 
nation quarters. Usually it enters homes by crawling up outside 
walls and into attics or upstairs bedrooms through cracks about 
window casings or between the side walls and roof. Such entranee 
into houses may be prevented by sealing these openings. A thor- 
ough application of one of the various fly sprays, particularly 
one containing DDT, in attics, closets, and upstairs bedrooms 
during late October or early November will alleviate this cluster 
fly plague. ' 
Control of the various species of Apauwlina is an exceedingly 
difficult task. It has been suggested that pupae of these flies, 
which may be found in nests of birds, should be destroyed as 
soon as nestlings have left; but this is nearly impossible when 
these parasites are abundant, and the procedure would obviously 
be costly. 
METHODS OF COLLECTING BLOWFLIES 
Adult blowfly collections may be made during most of the 
year in North America, at least from southern Canada south- 
ward. During warm periods of the winter, species which hiber- 
nate in the adult stage may be collected in favorable situations, 
but the best collecting for almost all the species is accomplished 
during the breeding season. 
In general, blowfly collecting may be divided into three 
different types: general collecting, trapping, and breeding or 
rearing. The last two methods are most productive. 
