f2 SCIENTIFIC REPORTS OF THE AGRICULTURAL RESEARCH 



been noticed to be strongly attracted to over-ripe cut mango 

 fruit. A plant (probably a Justicia), when in flower, 

 attracts flies of this species (and many other Diptera) in 

 large numbers. Maggots extracted from human nostrils, 

 from tumours, and from the foot of a cow suffering from 

 foot-and-mouth disease were bred out as flies which are 

 apparently Pycnosoma flaviceps. 



A Calliphorine Muscid, probably a species of 

 Chrysomyia, is always observed to follow Pycnosoma. It 

 is seen attracted to putrefying meat in the same way as 

 Pycnosoma. The chief points of interest of this species 

 are : — {%) the form and predaceous habits of tjie larvae, (ii) 

 females of this species are in the habit of producing pro- 

 geny of one sex only. 



The larvae of this species are hard-bodied and spinifer- 

 ous, each spine being finger-shaped, the apex again split up 

 into hook-like bristles. They are predaceous in habit es- 

 pecially at times of scarcity, which is not uncommon as the 

 number of larvae found upon a dead animal or piece of meat 

 is generally in excess of their food-supply. Experiments 

 conducted on the predaceous habits of these larvae show 

 that they prefer Sarcophaga and Pycnosoma to other 

 larvae, as the larvae of both these genera are fleshy, smooth, 

 and apparently harmless. Phorid larvae, excepting one 

 spinif erous species, are also liable to be attacked and, in the 

 absence of any such larvae, the Chrysomyia larvae fight 

 amongst themselves and devour each other. 



The habit of producing progeny of only one sex is curi- 

 ous. Instances of producing progeny of one sex amongst 

 insects, such as bees and Aphids, are well known but such 

 are usually the effect of Agamogenesis, i.e., a female with- 

 out sexual intercourse produces progeny. Several experi- 

 ments were carried out to see if Agamogenesis is common 

 amongst these flies. Batches of bred virgin females were 

 confined on several occasions with food, humidity, and all 

 other necessary conditions in a fly cage to see if they could 

 produce progeny without having any intercourse with males. 

 Side by side both males and females were also confined in a 



