BLOW FLIES. 325 



GENUS CALLIPHORA, ROBINEAU-DESVOIDY 



Medium-sized to large flies usually of a metallic colour. Posterior 

 dorsocentral and acrostichal bristles constant and well developed. Sterno- 

 pleural bristles arranged 2:1. Prothoracic stigmata brownish red. 

 Base of third longitudinal vein spinulose. 



This genus contains the ' Blue Bottles ', or ' Blow flies ', insects which 

 are familiar to most people. All the species are of considerable size, and 

 most of them are brightly coloured; some, " however, are of a bluish to 

 purplish tinge. They are widely distributed and are common in most 

 parts of the world. Calliphora erythrocephala, Macq., and C. vomitoria, 

 L., are common American and British species ; the former is also found 

 in North India. The larvae of C. vomitoria occasionally cause cutane- 

 ous myiasis in man and animals. As a rule, however, the larvae of the 

 Calliphora are useful scavengers, as they live by destroying animal refuse. 

 The female flies are readily attracted to the bodies of dead animals, in 

 which they deposit their eggs. Portschinski, who has studied the life 

 history of C. erythrocephala in Russia, points out that the female lays 

 from 450 to 600 eggs, 1 mm. in length ; in proportion to the size of the 

 fly they are remarkably small. 



GENUS LUCILIA, ROBINEAU-DESVOIDY 



Medium-sized flies either green or bluish green. Posterior dorsocentral 

 and acrostichal bristles constant and well developed. Sternopleural 

 bristles arranged 2:1. Prothoracic stigmata black. Third longitudinal 

 vein spinulose either at its base or throughout its length. 



The flies of this genus are distributed all over the world, but the 

 species are most numerous in tropical countries. In order to collect 

 them it is only necessary to place a piece of meat or the body of an 

 animal in the open, or even in a room, when several females will alight 

 on it and immediately lay their eggs. 



In South India Lucilia serenissima, Fabr., as a rule deposits its eggs 

 in meat and in the dead bodies of animals, but occasionally it will 

 oviposit in sores on the skin of sickly cattle ; this often occurs during 

 outbreaks of ' Foot and Mouth ' disease in Madras. Lucilia caesar, L., 

 a common European species, is also said to occasionally cause cutaneous 

 myiasis by depositing its larvae in the skin of man and animals. 



Lucilia serenissima is a common bazaar-fly in South India, and 

 feeds side by side with Musca nebulo on meat exposed for sale; it is 



