75 



The moths increased in number from the time they were first observed until, by the 

 3rd of June, in the early evening, when the field lay between the observer and the sun, 

 a perfect cloud of them could be seen hovering over the blossoms as far as the eye could 

 reach. They would spring up from under the foot like grasshoppers in a meadow on 

 a sunshiny day. It was also noticed that they were pairing freely at this time. 



On the 2 1th of June an examination of 177 heads of clover taken from the field 

 before mentioned showed 91 heads infested with the caterpillar of the moth as against 

 86 not infested. Many of the larvte were full grown and some were spinning their 

 cocoons. The hay was cut at this date. An examination the next day, June 25, of 48 

 clover heads takenfrom scattered launches on the college campus, showed 8, or 16| per 

 cent., of the whole infested. Examining 42 heads from a different field, cut on the 23rd 

 and 24th of June, only 3, or 7 per cent., were found infested. 



The damage was done by eating into the young florets, and later into the seed 

 vessels, causing the heads to dry up and the flowers to shell from the receptacles like 

 ehaff. 



The larva is a small, greenish white caterpillar, with a dark brown head, about .25 

 to .30 of an inch long when full grown, many of them becoming tinged with red 

 toward the hinder extremity as they approach the time of pupation. About the 24th 

 of June the adults had nearly all disappeared, a few stragglers only being found by dili- 

 gent search. Of a numVjer of larvae preserved in a breeding cage the first pupa 

 was found July 14, but a visit the same day to the field before mentioned proved the 

 second brood of the adults to have already appeared. An examination of dried bunches 

 of hay left on the field disclosed some larvte in the heads, which had spun their cocoons 

 to pupate, from which it is concluded that the caterpillars can live in the cut hay for 

 a considerable time if not hampered in their movements. An examination of the hay from 

 the same field stored in the barn showed all the larvse to be dead. A dead pupa was also 

 found, but nothing living. There were no empty pupa cases found to indicate that any 

 moths had escaped from the hay thus stored. It seems certain, theiefore, that everything 

 that was subjected to the pressure and heat incident to storage was killed. The remedy, 

 then, for this pest, which has caused the destruction of probably 50 per cent, of the 

 clover seed in the field observed, is to cut the hay soon after the first brood of larvse 

 appears, or in early June. The hay should be carefully cleaned from the field, -so that 

 no larvfe will find harbour in stray bunches which have not been gathered up. Scat- 

 tered clover growing by the roadsides and in the fence corners should also be carefully 

 mown at this time, and the heads at least disposed of in some manner to insure the 

 destruction of the larvje they may contain. This method can not but prove effective in 

 reducing the second brood of the moths, and will also operate against the clover-seed 

 midge Cecidomyia leguminicola. 



The track of the larva is very uniformly from the base of the head upward, and the 

 younger larvae are almost invariably found near the base, and beginning their work on 

 the florets there. It would seem, therefore, that the eggs are deposited at the base of the 

 receptacle, and the larvaj upon hatching may begin at once upon the older florets. In 

 working upward, roughly speaking, they usually form an irregular spiral track around 

 the receptacle. 



The delicate, white, silken cocoons of this insect are spun in the head among the 

 dried florets, frass and bits of eroded but undevoured flowers so covering them with brown 

 as to make them difficult of detection. The pupa- work their way entirely out of their 

 cocoons and drop to the ground before bursting their pupa cases, which may be found 

 in abundance on the ground from which a brood has just issued. 



The second brood was observed pairing during the last week of July, and August 

 5 the larvae were found in great numbers, one having at that time spun its cocoon 

 preparatory to pupating. The rate of growth would seem to establish that there are 

 three broods per year at Ames, and possibly, though not probably, four. [In advance 

 from a forthcoming bulletin. No. 14, of the Iowa Experiment Station.] 



