1900] PEAR GNAT MIDGE. 68 



Pear Gnat Midge. Diplosia pijrivora, Riley ; Cecidu)nijia ni<jra .-, 

 Meigen and Schmidberger ; C. pyricola /, Nordlinger. 



DiPLOSis PYKivoRA. — Female, magnified ; lines showing natural size. Laiva and 

 pupa, magnified. Abortive Pear. Gnat and pupa, after Prof. Riley. 



The observations of the Pear Gnat Midge during the past season 

 call for notice, as (connected with those of the two preceding seasons) 

 they show the attack as being now widely injurious, and with a 

 capacity of spreading where not attended to ; but also that, where duly 

 attended to, much may be done to keep the destructive maggot attack 

 in check. 



As I cannot easily give the main points of the life-history of the 

 Midge, and the method of the attack, in shorter form than as I have 

 condensed them at p. 98 of my Twenty-third Annual Report, I append 

 them with very little alteration. 



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 longish 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 larvte from them may be 

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

 embryo Pear, where they separate and eat away the substance 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. 

 At this stage — that is, when the young Pear is destroyed by the 



