14S 
kept burning all night for fourteen nights between May 20 and June 
23 inclusive, and were visited at frequent intervals during each of 
these nights. The weather was so cold during four nights that the 
May-beetles were not flying, and no account is taken of these nights 
in this discussion. 
The total product of the twelve traps, thus maintained for ten 
entire nights, was 142 specimens of May-beetles of the genus Lach- 
nosterna and 25 specimens of Cyclocephala. No account is taken of 
the latter because their food habits are very different from those of 
Lachnostcnia. The average product of a lantern in one night was 
only 1.2 of the true May-beetles (JLachnosfcrna), and the largest 
catch of any one night was 40 specimens on June 18, or 33/^ per light. 
The largest collections were made on three nights between June 9 
and 18 inclusive, these averaging 33 per night, or about 3 to each 
trap. The two collections of May, made on the 26th and 31st of 
the month, averaged only 6 beetles per night, or i to each two traps. 
A single light-trap of the same kind, exposed at night without a 
screen, for ten minutes May 21 and for thirty minutes May 23, close 
to willow-trees at the border of this field and near the cemetery 
above mentioned, yielded 1 1 May-beetles on the first night and 127 on 
the second — seventy times as many taken in ten minutes by one trap 
near these trees as were taken at approximately the same date by a 
trap exposed all night in the open field. There could be no question, 
consequently, that very nearly all the May-beetles of this neighbor- 
hood were concentrated in the trees at this time. 
New data have been obtained by our collections and observations 
of recent years with regard to the nightly movements of the beetles, 
and these are thus summarized by Mr. J. A. West, who had charge 
of this work for 1906. 
"There is a regular migration of beetles from the fields to the 
trees in the evening. It takes place in June just about dusk — from a 
few minutes before to a few minutes after eight p. m. The move- 
ment of the beetles is almost simultaneous from the different fields. 
An observer in one field can scarcely move to another and hope to 
see the migration. It is usually but a few seconds from the time 
its beginning is noticed in one place until a companion observer will 
report its commencement perhaps a quarter of a mile away. Beetles 
were found rising from the ground in fields of oats, in pasture, old 
meadow, clover, alfalfa, and in corn. They were most abundant from 
old pasture and least numerous from alfalfa and corn. They were 
observed coming from the ground in considerable numbers in oats 
and clover fields. The following species are mentioned in the order 
