312 MEDICAL ENTOMOLOGY 



pests. Hewlett records a species of Drosophila from Northern India 

 which completes its whole life history within a week ; this is, as he points 

 out, the shortest life history yet recorded for an insect with a complete 

 metamorphosis. 



In Madras there are two species which are commonly seen hovering 

 about ripe fruit, especially during the rainy season ; both are infected 

 with a species of herpetomonas. In France another species, Drosophila 

 conftisa, is commonly infected with Crithidia drosophilae, Chatton and 

 Alilaire. 



In order to breed these flies it is only necessary to place some bananas 

 in a tray, and allow them to become over-ripe ; the flies will soon collect 

 on them in large numbers and deposit their eggs, which are very small 

 and have tw r o long filamentous processes. If the fruit is not disturbed 

 the pupae will be found in large numbers collected on the outside of 

 the bananas, and along the sides of the tray. As in the case of 

 the dung flies the pupae should be placed in the breeding jar and the 

 imagines fed on fruit ; the larvae should always be examined for the 

 flagellates. 



THE CALYPTERAE 

 FAMILY ANTHOMYIDAE 



Small to medium-sized flies in general appearance resembling those of 

 the genus Musca ; greyish or brownish black in colour, rarely metallic. 

 Male less dichoptic than the female. Antenna of the muscid type ; 

 arista either plumose or bare. First posterior cell widely open. 

 Abdomen composed of four or five visible segments, rarely armed with 

 bristles. Squamae well developed. 



This family contains the genus Homalomyia (Fannia), the species of 

 which have domestic habits and regularly enter human habitations. 

 H. canicularis is the best-known example, and is popularly spoken of as 

 the ' Lesser house fly ' ; its larvae have been recorded from the human 

 intestine. The larvae of the majority of the Anthomyidae are vegetable 

 feeders, and many are destructive to garden produce. Others again 

 breed in dung and the decomposing bodies of animals; these forms are 

 usually infected with natural flagellates. Mackinnon records Herpetomo- 

 nas muscce domesticae from the larva of Homalomyia corvina from cow 

 dung. In Madras there are several of these dung-frequenting antho- 

 myids which are also infected with flagellates ; one in particular can be 

 caught in large numbers by placing some decomposing meat in the open. 



