REPORT OF THE STATE ENTOMOLOGIST I913 1 75 



scattering individuals may emerge at almost any time between the 

 middle of July and the first of September. The Qgg period in early 

 July is three days. Most of the injury to the seed crop is inflicted 

 during the last two weeks of August and the first two weeks of 

 September, at a time when the larvae are most numerous in the 

 clover heads. Most of the insects winter as larvae and emerge as 

 flies the following May. A few, however, transform and produce 

 flies in early September or even later. Midges were obtained in 

 the insectary without artificial heat as late as October ioth and in 

 a warm room they were reared throughout the winter. These late 

 appearing flies are unable to propagate their kind, owing to the 

 frost killing the flies, and especially to the green clover heads dying 

 before the larvae of the third generation can complete their growth. 

 There is a possibility that larvae from flies appearing in early 

 September may be wintered in safety. Doctor Folsom concludes 

 that in central Illinois there are two full broods and a partial third 

 generation. 



Habits. The eggs are always laid in green flower heads and 

 chiefly during the warmer part of the day, the female being fre- 

 quently so busy as to pay no attention to slight interruptions. Stand- 

 ing on the outside of a green clover head the female inserts her long, 

 slender ovipositor among the florets and works it deeper and deeper 

 until it can go no further. The female then becomes quiet until an 

 egg is laid, the entire process usually requiring 5 minutes and often 

 10 to 15 minutes. One female may lay several eggs in a clover 

 head though she appears to make it a rule to distribute her eggs 

 among a number of plants. Many females may oviposit in the 

 same head and, as a result, more larvae hatch than can possibly 

 find food. Thus, in one head of 80 florets Doctor Folsom found 

 106 eggs. Once in a while an tgg is laid on a petal or on the calyx 

 itself but almost always it is glued to one of the hairs of the 

 immature calyx, the glue often forming quite a perceptible mass. 

 The abundance of the larvae in a head is confirmed by the follow- 

 ing observation from Professor Comstock: "A head, which one 

 moment is motionless and at a glance seems to have no animal life 

 about it, becomes the next fairly swarming with these maggots. 

 From nearly every closed floret one emerges and wriggles violently 

 until it works itself away so far that it falls to the ground. A 

 batch of clover which was observed by Doctor Howard on the 

 morning of May 23d last seemed entirely alive with the issuing 

 maggots and their accompanying parasitic foes." 



