132 THE CANADIAN ENTOMOLOGIST 



2. Deposits of drift vary with the strength of the wind. 

 When too strong, the sand is disturbed and many insects are buried 

 in it. Long, evenly-rlinning waves driven by a steady on-shore 

 breeze give the best deposits. 



3. The proportion of insect material in the drift varies with 

 such purely local and accidental causes as the dumpings of straw 

 and ashes from lake steamers, and with many natural causes, the 

 two mcst important of which seem to me to be: — 



(a) Storms, with attendant floods, that carry vast quantities 

 of plant fragments into the lake. Occasionally an abundant ac- 

 cumulation of insects may be entirely hidden amid a still more 

 abundant windrow of this sort of material. Mr. Schwarz once ex- 

 pressed the opinion (1890) that storms have nothing to do with 

 the insect drift; and while it is true that the deposits occur whether 

 there be storm.s or no, yet I am sure that if an ofT-shore storm wind 

 blows while any insect is swarming, within a few days that insect 

 wall appear in unusual abundance in the drift-line on some lee shore. 



(b) Emergence periods of particular insects. This is the 

 mcst significant of all factors for the collector to bear in mind. 

 What wind and waves gather depends on what nature has brought 

 forth, ready to be gathered. Extraordinary accumulations of May- 

 beetles and of Mayflies are well known to occur at regular times. 

 It was an extraordinary shore deposit of black crickets that first 

 interested me in the insects of the drift line (1900). Hancock has 

 recorded (1894) for another species just the conditions of swarming 

 and flight that made ready this crop of crickets that was gathered 

 by the storm wind. Just after the publication of my paper (1900) 

 recording the accumulation of the crickets in the drift on the shore 

 of Lake Michigan on the 13th of August followang a storm from 

 the west, a friend wrote me that there had been an extraordinary 

 swarming of the same species in the streets of the city of Rockford, 

 111., (some 65 miles westward) on the 11th — the day the storm oc- 

 curred. In my August collecting of 1916 I found but four speci- 

 mens of this species. 



Every one who has run a trap-lantern or who has sugared for 

 moths knows how much atmospheric conditions have to do with 

 bringing insects out in abundance. It is the night of high humidity 

 just before a rainstorm that finds most of them astir. The col- 



