348 Mr Lamb, Insect Oases 



have similar cases recorded, but unfortunately the observations 

 necessitate a very long and close acquaintance with a given district. 

 All the insects mentioned below are quite capable of flight, but 

 are usually very sedentary in habit, being only obtainable by 

 "sweeping." 



Lucinafasciata Meigen. This South European species was first 

 recorded many years ago from Ireland, and was rediscovered in 

 England on the coast near Weston, Somerset, by the author. It 

 occurs very sporadically in the locality under consideration, but 

 in one very restricted area it is quite common, the boundary of 

 its distribution being reasonably definite, though no observable 

 physical boundary is to be seen. 



Oxyna flavvpennis Loew. This species is apparently extremely 

 rare although it is said to breed in Achillea millifolium; the late 

 Mr G. H. Verrall in 40 years of most careful investigation only 

 found two specimens. In the present locality it occurs in great 

 numbers on the sheltered side of one out of many of the tamarisk 

 hedges that intersect the commons, but is practically restricted 

 to some 40 yards of the hedge. 



Afhaniosoma quadrinotatum Becker. This is a species first 

 described from the Canary Islands and afterwards found in Spain. 

 It is confined to a similarly restricted spot associated with Matri- 

 caria, which is, however, quite abundant elsewhere where the 

 insect is absent. 



Syntormon mikii Strobl. This is another Spanish species which 

 occurs only in a very small marshy hollow near the commons. 

 That same hollow produces three other species of the genus, 

 namely pumilus, monilis and the ubiquitous fallipes. 



A second type of homogeneous locality is afforded by the spots 

 where small streamlets run on to the sands of the various bays 

 that break the coast line: these localities are all practically ahke 

 in character and flora. On the banks of one of the streams, and in 

 an area of but a few square feet, occurred our last example. 



Ochthera mantispa Loew, an insect first described from Rhodes, 

 and found round the Mediterranean littoral. This singularly 

 isolated colony persisted for some years, but is now probably 

 extinct owing to disturbance of the natural conditions by visitors 

 to the bay. In spite of assiduous search no other colony has been 

 found. 



It will be noticed that all the species referred to, with the 

 exception of the Oxyna, are of southern distribution. Other 

 southern insects have been found in the district, but are not so 

 striking in their isolation. Two other rare flies are also found 



