44 REPORT ON INJURIOUS INSECTS FOR 1904. 



Writing in 1885, Dr. Riley expressed some doubt as to 

 whether this species was the same as Diplosis nigra (Meigen), 

 the habits of which are very similar, and were first described by 

 vSchmidberger in 1831. According to Dr. Jos. Mik, nigra is 

 practically a lost species. Writing to Dr. Riley in March, 1885, 

 this dipterologist says, "If you will allow me to advise, you should 

 describe your species from fresh and dry specimens as new, and 

 could add the above names (nigra, Meigen, and pyricola, 

 Nordlinger.) as doubtful synonyms. I believe that no error 

 would be committed by adopting this course." Dr. Riley took 

 this course and described the insect under the name of Diplosis 

 pyrivora, by which it is now generally know r n. 



LIFE-HISTORY AND HABITS. 



The fly, which is nearly one-tenth of an inch in length, 

 usually makes its appearance early in April, but the exact time 

 varies, according to locality and the condition of the season. 

 The eggs are deposited in both the unopened flower buds and 

 expanded blossoms, being introduced by the long ovipositor 

 of the female midge. In the former condition the petals are 

 pierced and the eggs are found in a little heap lying upon the 

 anthers, but when an expanded blossom is attacked the pistil 

 or ovary is pierced. Schmidberger ( [ ) thus describes the 

 process of depositing the egg in D. nigra, " In the spring of 

 1832, my first business was to look all round the garden for 

 these midges. When the blossom buds of the pear tree were 

 so far developed that in the single blossoms a petal showed 

 itself between the segments of the calyx, I found the first midge 

 in the act of laying its eggs in the blossom, this was on the I2th 

 of April. It had fixed itself almost perpendicularly in the 

 middle of a single blossom and having pierced the petal through 

 with its long ovipositor, it laid its egg on the anther of the still 

 closed blossom. The female was about seven and a-half minutes 

 laying her egg. When she had flown away, I cut the pierced 

 bud in two and found the eggs lying in a heap one upon another 

 on the anthers. They were white, longish, on one side pointed 

 and transparent and from ten to twelve in number. I after- 

 wards found several midges engaged in laying their eggs as late 

 as the i8th of April, from which day they ceased to appear in 

 the garden." 



The number of eggs varies, but from a large number of 

 fruits examined, thirty-eight maybe taken as the average, some- 

 times only ten or twelve are deposited, while in other cases as 

 many as fifty are present. The eggs hatch out in from four to 

 six days and the larvae a series of tiny yellowish-white maggots 

 make their way into the fruitlets, which after about a fort- 

 night commence to^ swell and assume an irregular distorted 



i. In Kollar's Treatise on Insects Injurious to Gardeners, &c. English trans. 1850, p. 293. 



