288 



INJURIOUS INSECTS AND FUNGI. 



[Dec. 1898. 



The species Merodon narcissi (clavipes), Curtis states, is the 

 only one discovered in this country and that specimens of this 

 are very seldom found. Walker in his Diptera only describes 

 Merodon clavipes, and adds that it is very rare. 



The fly appears in May, and has been seen flying about 

 daffodils and similar plants. It is a large insect, nearly three- 

 quarters of an inch long, with a wing expanse of nearly one 

 inch, and is more like a small bee than a fly. The body is 

 broad, blue-black with metallic lustre, having transverse bands 

 of a golden colour. The wings are grey with brown "shades and 

 fringed with yellow. The legs are short and black, and there 

 is a large tooth on each thigh. The eyes of the female fly 

 are set widely apart ; those of the male converge. The body 

 of the female is more round thai that of the male, which tapers 

 at the extremity. 



It is not known where the egg is laid, but probably upon 

 the plant and near to the bulbous part of it. The larva is 

 found in the hearts of the bulbs, feeding upon their succulent 

 parts and causing their decay. The correspondent who for- 

 warded the infested bulbs states that in every case " the grubs 

 seem to enter at the bottom of the bulb and work their way up 

 to the top." 



The larva is nearly half an inch long when moving. It 

 generally lies in a curved position, with its cylindrical body 

 folded up, so that its length is not seen until it moves. The 

 colour of its body is ash grey, and brown upon the much 

 wrinkled folds. It has no head, but the upper extremity is 

 pointed and somewhat flattened at the end, immediately under 

 which there is the mouth, which is a mere slit, furnished with 

 two formidable black hooks ; above these are two pink divided 

 horns. Upon each segment there is a crooked bristle, and at 

 the lower end of the body, also rather pointed, a shining black 

 warty excrescenc3 projects, upon which two spiracles are placed. 

 Pupation takes place in the earth in a slight silken cocoon. The 

 pupa is dark brown, somewhat oval, v;ith two anterior horns. 



It is uncertain how long the larvae continue to feed in the 

 narcissus bulbs. Some were feeding at the end of November, 

 while others had pupated by that time. 



Prevention and Remedies. 



From the information received when the infested bulbs were 

 sent, it appeared that a considerable quantity had been imported 

 from the continent, and this seems to be the explanation of so 

 large a number of the Merodon larvae having been found in 

 parts of Cornwall. As this insect is comparatively abundant in 

 some continental countries, it is most desirable that imported 

 bulbs should be carefully examined before they are planted. 



Where infestation is suspected in beds of narcissus, the plants 

 should be examined, and, if decay is noticed, the affected bulbs. 



