Observations on some species of Orina. 7 



One or two larvae were deposited by beetles taken later, 

 up to August 6th, but none after. Whether they 

 naturally finish the process at this date I don't know, but 

 it is very probable. Still it must be noted that no laying 

 beetles were taken at later dates, and that specimens 

 brought home to England were fed on an unacceptable 

 diet of which they partook most sparingly. 



The beetles during August and September died con- 

 tinually by ones and twos, but there were still a dozen 

 or so alive on October 1st, and one that died at that date 

 was very shrunken, had no food in the alimentary canal, 

 but had some small eggs in nearly all of the ovarian tubes. 

 About half-a-dozen were still alive on November 4th. 



The beetles in captivity were frequently found to be 

 pairing, but without result. These facts suggest that 

 there may be something more to learn, if observations 

 could be made when a good supply of the natural food 

 was obtainable. 



I have but slight acquaintance with the literature of 

 viviparity in insects, and consequently do not know whether 

 anything very definite has been recorded as to where the 

 ova are fertilised and where development within the ovum 

 takes place. In the " sheep- tick " only one egg appears 

 to be matured at a time, and this seems to rest for a con- 

 siderable time in the dilated oviduct which acts appar- 

 ently as a uterus. In Melophagus it may therefore be 

 that fertilisation of the ovum takes place much in the way 

 that it does in the majority of insects, viz. in the oviduct 

 and from a spermatheca. In Scatophaga and other dip- 

 terous genera, ova are said to be retained in a dilated ovi- 

 duct till they hatch, larvae being laid. 



In Orina vittigera this is certainly not the case ; the 

 development of the ova takes place in the ovarian tubes, 

 of which there are two bundles of about 20 in each, 

 from each of which bundles a tube meets its fellow to 

 form the common oviduct, the parts being arranged in the 

 same way as in the majority of insects. In the tubes 

 larvae ready for hatching are found at their lower ends, 

 whilst higher up are smaller larvae. The appearances 

 show that the larva grows considerably in the oviduct 

 after it has developed sufficiently to show eye-spots, and 

 still smaller bodies further up are probably not eggs for 

 fertilisation, but partially developed larvae. Some of these 

 are very similar to the larvae just showing eye-spots, and 



