MUSC1DJE. 141 



flies, members of the genera L^tcilia and Calliphora. As 

 widely known are the stable-fly or cattle-fly, Stomoxys, and 

 the horn-fly, Hcematobia. 



The larvae of the house-fly live, for the most part, in dung 

 or manure, but will thrive in almost any kind of filth ; I have 

 reared them from the decaying material in the bottoms of 

 spittoons filled with tobacco. The female lays about one hun- 

 dred and fifty eggs, which hatch in one or two days, according 

 to the weather. The larvae attain their full development in 

 from five to seven days, and then, crawling into some secluded 

 place, transform into pupae, from which they emerge in about 

 six days as mature insects, those of the autumn broods 

 remaining over winter as puparia. In partially secluded spots 

 the mature fly will sometimes survive the winter. The clus- 

 ter-fly, Pollenia rudis, is yet more remarkable in this last 

 respect. Often in early spring, or even during mild days of 

 the winter they may be observed crawling about over the snow 

 in numbers. They are stupid and slow and have received the 

 name of cluster-flies from their habit of congregating in clus- 

 ters about dwellings. They resemble a blow-fly somewhat, 

 but will be distinguished by the presence of short, depressed, 

 sparse light colored hairs on the thorax. The larvae of species 

 of Calliphora, especially of C. vomitoria, are better known, 

 perhaps than those of any other insect. They are the common 

 blow-fly maggots of fresh and decaying meats and vegetables. 

 The cooking of corned beef or turnips or cabbages during 

 warm weather is sure to attract numbers of these insects, 

 which are quite noticeable for their loud humming, and head- 

 long flight. In the arid regions of northern Wyoming, the 

 writer has seen them in extraordinary numbers, many 

 miles from the nearest human habitation. Either their eggs 

 or the newly hatched larvae are deposited upon meats, and 

 only a day or two is sufficient to transform the mass into a 

 creeping mass of disgusting maggots. The larvae of species of 



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