J. E. Collin 87 



flies hatching out in January in a warm room were found to copulate 

 and when given fresh young plants, laid eggs which hatched in a few 

 days. 



EGGS. 



In the autumn and spring the eggs are laid on the leaves of the 

 young plants (preferably on the underside), or on the stem close to the 

 ground, Kurdjumov (1913) said at the level of the soil. Krassiltchik 

 (1912?) in Bessarabia found no eggs on the leaves but all on the young 

 stems. Baranov (1912, Moscow) on the other hand found them mostly 

 upon the upper side of the leaf near the stalk, or (1914) on both sides 

 of the leaves, sometimes on the stalk near tillering knot. In the summer 

 the eggs may be laid on the sheaths enclosing the ears, on the panicles 

 of oats, the young corn of oats and barley, or on wild grasses. A female 

 may lay from 20 (Lindeman, vide Kulagin, 1913) to 30 (Rorig, 1893) or 

 according to Wahl (1914) 70 eggs; and the eggs take from three to 

 seven days to hatch (three to four days, Wilhelm, 1891 ; three to seven 

 days, R(')rig, 1893 ; four days spring, seven days autumn, Baranov, 1914). 

 According to Dobrovliansky (1915) the maximum number of eggs laid 

 by a female in one day is six, and while in moist air and a high tempera- 

 ture the eggs may hatch in three days, dry air will kill them. 



LARVAE. 



The young larva of the autumn and spring broods makes its way 

 into the young stem and eats the tender central leaves and shoot, 

 ultimately killing the shoot which in the meanwhile may produce side 

 shoots. According to Krassiltchik and Vitkovsky (1913) the newly 

 hatched larva may mine the leaf upon which it was laid very extensively 

 before working its way into the stem. Several writers have noted that 

 a larva can migrate from one shoot to another. Normally only one larva 

 is present in each shoot, but as many as ten larvae have been found in 

 a single plant. The summer larvae live in the summit of the stem, feeding 

 upon the hidden ears or panicles, on the young corn in the ear or panicle, 

 or in the stems of grasses. The spring and summer larvae may feed for 

 14-15 days (Baranov, 1912), three weeks (Ritzema Bos, 1891), three to 

 four weeks (Kulagin, 1913), or five weeks (Rorig, 1893), while the 

 majority of writers are agreed that the autumn larvae normally winter 

 in that state and do not pupate until the early spring. Baranov (1912) 

 gave the proportion of larvae to pupae found in the winter as 100 to 

 10-15. Dobrovliansky (1913) found in the Government of Kiev that on 



