
862 THE AMERICAN NATURALIST.  [Vor. XXXVI. 
and the relative abundance of the various forms. For example, 
we found (1) the occurrence was in succession ; (2) the popu- 
lation increased apparently at times when an offshore wind 
was followed by a lake breeze; (3) it also increased with the 
temperature; (4) the greatest numbers occurred on beaches 
of low gradient and smooth, fine sand; (5) the abundance of 
scavenger forms depended upon the abundance of dead her- 
bivorous and predaceous forms and other refuse; (6) the abun- 
dance of predaceous forms depended upon the presence of the 
active scavenger and herbivorous and smaller predaceous forms. 
I gratefully acknowledge the kindness of Dr. Charles B. 
Davenport and Mr. Charles C. Adams, and present my thanks 
for their assistance in identification and for valuable advice 
and suggestions. 
HULL ZOOLOGICAL LABORATORY, 
July 18, 1902. 

List. 
Of the one hundred and fourteen species collected fifty-one 
were identified, the whole collection being placed in the follow- 
ing orders and (where possible) families : — 
Coleoptera, 75: Carabida, 33; Scarabaida, 10; Chryso- 
melidz, 9; Coccinellide, 7; Staphylinide, 3; Hydrophilidz, 
3; Cerambycide, 2; Elateride, 2; Silphidz, 1; Histeridz, 1; 
Halipide, 1; Lucanidz, 1; Curculionide, 1; Calandridz, 1. 
Hemiptera, 11: Pentatomide, 5; Lygæidæ, 2; Reduviide, 
I; unknown, I. 
Diptera, 10: Muscidae, 5; Syrphidz, 2; Phoridæ, 1; Tach- 
inida, 1 (?); unknown, 1. 
Hymenoptera, 9: Apidæ, 4; Formicide, 1; Vespide, 1; 
Andrenidz, 2; Tenthredinide, 1. 
Lepidoptera, 3: Arctiidz, 2; Noctuide, 1. 
Trichoptera, 2: Phryganeide, 2. 
Neuroptera, 2 : Chrysopide, 2. 
Orthoptera, 1: Blattidz, 1. 
Arachnida, 1 : (Lycosidz ?) 
