8i [April. 



After tny return home, on looking over some insects taken by my 

 sou in Italy in 1895,1 was pleased to see another specimen o£ appa- 

 rently the same fly, but this proved to be a (J. On looking at its 

 face I found it was entirely white, just as is the face of the (J 

 Prosopis, in other respects it closely resembles the ? , only all the 

 segments of the abdomen are red ; the ,^ of the Prosopis, on the other 

 hand, has the abdomen as a rule entirely black, although a variety is 

 recorded with the base red. 



Mr. Verrall, to whom I am indebted for the determination of the 

 flies, tells me that he has noticed other species of Paragus about with 

 small bees, such as Halictus, &c., and has always suspected them as 

 being associated in some way. 



What strikes me as being so especially remarkable is the great 

 resemblance in the facial markings of the two insects. Any one who 

 has done much collecting among the Fossorial Hymenoptera must 

 know well how the inquiline flies that associate with them sit close by 

 their burrows, with the silvery hairs of their faces glittering in the 

 Bun, exactly like those of their host ; and if there is a real association 

 between the Prosopis and Paragus, it is certainly noteworthy that 

 here again the likeness should be specially noticeable in the facial 

 markings. That this similarity should occur in both sexes seems to me 

 still more extraordinary. 



From many points of view it might be advantageous to the $ fly 

 to resemble the ? of its host ; but how could such a resemblance 

 profit the (J?, unless possibly it has to hover about the burrows of the 

 bee in attendance on its ? , in which case its similarity to the ,^ bee 

 might be useful to it in escaping detection : but one feels that such a 

 theory implies great want of perception on the pan of the bee, and 

 probably some far less apparent explanation will be discovered to 

 account for resemblances of this sort. 



St. Ann's, WoMng : 



February 6th, 1900. 



NOTES ON CERTAIN DIPTERA OBSERVED IN SCOTLAND DURING 

 THE YEARS 1898-99. 



BY COL. J. W. YERBURY, late R.A., F.Z S., &c. 



(^Concluded from page 57). 



COEDTLURA EUFIMANA, Mg. 



The first specimens of this species found in the British Isles, at 

 any rate of late years, were taken by myself at Nethy Bridge on 

 August 4th, 1S98 ; these specimens were identified by me on my 



