172 D. d'emmerez de charmoy. 



On tlie other hand, information regarding occurrences during the past twenty 

 years is much more precise and a review of it is of interest, inasmuch as it affords 

 indications of the channels of introduction and the harm that has been caused thereby. 



Phytalus smithi. 



Though this beetle was detected in Pamplemousses only in the year 1912, there 

 is no doubt that its introduction dates back to at least ten years before its existence 

 was noted. The infested area, the large number of insects destroyed in the first year 

 1912, the subsequent infestation of other localities, and its rate of spread in these 

 locahties, leave no doubt as to the time that the insect must have taken to spread 

 over so large an extent, which in 1912 was about 1 mile in radius. 



Though it is impossible to make any definite statement, the probabiHties are that 

 the insect was originally introduced through the Royal Botanical Gardens, 

 Pamplemousses, by means of cane plants imported from Barbados, packed in soil in 

 Wardian cases. 



A Cecidomyiid Fly. 



This Cecidomyiid, which it has not been possible to identify up to now, and the 

 origin of which cannot therefore be traced with certainty, was probably imported in 

 the year 1909 with a lot of mango plants from India by a sugar estate proprietor of 

 Grand Port. 



A few years later, the presence of this insect was revealed simultaneously at Port 

 Louis and at Mahebourg, on mango trees, the leaves of which bore small conical 

 galls grouped together irregularly and containing Cecidomyiid larvae. These 

 locahties were at first the only two affected, but the infestation was then so 

 widespread that there was no hope of destroying the pest. After having remained 

 localised in these two places until 1918, this fly was found at Grande Riviere, then at 

 Riviere Noire, and can now be seen in almost all locahties in the island, in varying 

 numbers. 



Dacus d'emmerezi. 



This Trypetid fly was described by Professor Bezzi in 1917 in the Bulletin of 

 Entomological Research. It is not an indigenous species, as its presence was only 

 detected in 1915, in the course of investigations concerning Dacus sygmoides. It 

 would be difficult to say whence it came, though one might reasonably suppose that 

 it has been introduced from Madagascar by means of cucurbitaceous fruits, as it 

 would have been difficult in infested fruits coming from a more distant place to pre- 

 serve the healthy appearance which alone could have warranted their safe transit. 



This species is nowadays far more common than Dacus sygmoides, and exhibits a 

 partiahty for marrows and pumpkins, constituting a pest in the cultivation of these 

 vegetables. 



Echidnophaga gallinacea. 



This flea found its way into Mauritius on fowls imported from Vohemar in 1913, 

 and others which were introduced from South Africa in 1914. The insect proved 

 troublesome at Mapou during the early days of its introduction ; it has not spread 

 to the other districts up to now. 



