1899] PEAR GNAT MIDGE. 93 



scarcely any enquiries were sent me regarding the infestation, and 

 it would not have been worth while to enter on the subject again 

 excepting that from this very circumstance (of ?to» -observation), it 

 appeared of serviceable interest to ascertain whether the attack 

 recurred at the localities at which it had been reported as noticeably 

 injurious in 1898 ; and if not, to what circumstances or what preventive 

 measures the non-reappearance might be ascribed. 



Through the courtesy of my correspondents, who are all well 

 qualified to report on the subject, I have been furnished with the infor- 

 mation requested, which I give (p. 94, and onwards), appended in each 

 case to a note of some of the points of appearance in the preceding 

 year, and I trust it will be considered, on glancing over the summary 

 following the notes, that we have now quite sufficient practical in- 

 formation before us to enable us to keep the attack of this Pear Gnat 

 Maggot {Diplosis pyrivora) in check. 



The Gnat, or Midge, which causes the injury is a very small two- 

 winged fly, gnat-like in appearance, and about the twelfth of an inch 

 or rather more in length (see figure, magnified, and lines giving natural 

 length). The general appearance is greyish or black, but, when 

 examined in detail, the head is black, bearing a tuft of yellow hairs ; 

 thorax black, but with some grey markings, and varying in appearance 

 according as to whether it is looked at from before or behind. A tuft 

 of yellow hairs placed at the root of each of the dusky wings, which 

 are clothed and deeply fringed on the hind margins with black hairs. 

 Abdomen dark brown, clothed with long whitish hairs; legs brown, 

 clothed with white hairs, more dense on the upper surface.* 



The method of egg-laying is considered to be that when the Pear 

 blossom-buds are so far advanced as for a single petal to show itself, 

 the Pear Midges deposit their eggs within by piercing the petal with 

 the ovipositor, and laying their white lougish eggs, up to as many as 

 ten or twelve in number, on the anthers within the still unopened 

 blossom-bud; but they have been recorded by one observer as egg- 

 laying in the open blossom. The eggs are stated to be so quickly 

 hatched in warm weather that the little larvse from them may be 

 found on the fourth day after deposit. They bore into the core of the 

 embryo Pear, where they separate and devour in different directions. 



The maggots are about one-sixth of an inch in length, narrow, 

 legless, smallest at the head and tail. Within the young (or it may 

 be said the embryo) pears the midge maggots live and feed until they 

 have attained their full size, which may be about the beginning or 

 middle of June, and the infested Pears may often, though not always, 

 be known by their knobbed irregular growth and discoloured patches. 



* For full and clear description of the imago or perfect Gnat Midge of 

 D. pyrivora, see paper on this insect by E. H. Meade, in ' Entomologist,' vol. xxi. 



