H. M. Morris 107 



Other records mention Bihio hortulanus larvae as damaging sugar 

 beet (25), spring barley and wheat (18), the damage in the latter instance 

 being so severe that many fields had to be ploughed up and resown. 



Curtis (6) states that Dilophus febrilis larvae cause much mischief in 

 gardens. He found them on the decayed portions of planted potatoes 

 and also on the tubers, and in flower pots. 



Larvae of Bibio abbreviatus are reported by Strickland (24) to have 

 damaged celery plants. The soft tissue between the fibro-vascular 

 bundles of the stalks was eaten away to a depth of l"5mm., and the 

 larvae also burrowed slightly into the stalks. Owing to the large number 

 of larvae the damage was extensive. In this case the larvae are thought 

 to have been brought to the plants in manure. 



Some instances of believed damage by the adults of this family are 

 recorded. Lyonet(i4) believed that the adults of Bibio Marci damaged 

 the buds of fruit trees, and other writers believed that the adults of this 

 family damage fruit blossom, but it is unlikely that the damage was due 

 to this cause, the flies being more probably beneficial in assisting pollina- 

 tion (31). The adults of Dilophns febrilis are mentioned as being believed 

 to cause damage to hop-cones, but any damage is probably due to their 

 being dried in the cones (27). 



Bibio albipenviis, which appears to be very common in the United 

 States of America, is considered to be harmless. The larvae are said 

 to feed on dead leaves and stems (7), and they are also mentioned as 

 having been found feeding on oak galls (29). which appears unusual, 

 unless the galls had fallen to the ground. 



The larvae of Bibionidae appear to occur very commonly in cow-dung 

 and manure (S, 15) and it seems probable that in many instances the larvae 

 have been carried to the plants which they were found damaging in 

 manure. Many of the plants mentioned as being attacked are usually 

 grown with heavy applications of this material. 



Theobald (27) states that vaporite and injections of bisulphide of 

 carbon into the soil were found to kill the larvae. He also recommends 

 trapping the larvae by burying old roots in the soil, and then digging 

 them up early in March and destroying the larvae found feeding on them. 

 He also found soot and lime effective in dealing with the larvae. 



Carpenter (4) states that the larvae " seemed to be but little affected by 

 the dressings usually applied for killing or repelling underground insects." 

 He states that various birds, including domestic poultry, devour the 

 larvae readily. Bibio larvae of several species have been found in the 

 food of rooks, starUngs and chaffinches (2s). 



Ann. Biol, iv 8 



