46 Journal New York Entomological Society. [Vol. xxi. 



temperature of 105 degrees Fahr. (and some Hydrophilidse in still 

 warmer water) while Deronectes griscostriatus De G. swarms in the 

 icy springs or " lakes " above the tree line in the White Mountains, 

 and in Labrador. As a rule, the species of Ccelamhus, Hydroporus, 

 Ilybius, Agabiis, Colymbetes and Dytisais are most abundant in colder 

 climates, while Canfhydrns and its allies, Laccophilus, Hydrovatus, 

 Celina, Copelatus and Cybister are best represented in warmer regions. 

 Excluding the very large bodies of water — the large rivers, the 

 big lakes, and the extensive swamps, — which, as before stated, are not 

 favored by the Dytiscidse, the various water bodies may be con- 

 veniently discussed, with reference to these beetles, under the fol- 

 lowing four heads. 



I. The pond of the open meadow. 



II. Ponds and pools of the forest with sphagnum as the charac- 

 teristic living plant form, and dead and rotten leaves for a bottom. 



III. Running brooks or small rivers. 



IV. Small springs or wells. 



I. The Meadow Pond. 



This is the ordinary hunting ground of the collector. The other 

 places are quite commonly neglected. 



The Dytiscidse living in the typical meadow pond are well de- 

 scribed by Professor James G. Needham in his paper in the American 

 Naturalist, August, 1907, in which is given a list of 29 species found 

 in the " Gym " pond on the campus at Lake Forest, Illinois. 



This pond is described as an artificial one, made by damming a 

 short spring-fed brook, in which after several years conditions have 

 become quite natural. The pond is about 200 feet by 100 feet, 15 

 feet deep near the dam, and shallow at the other hand, where it is filled 

 with a dense clear growth of cat-tails (Typha), with very little other 

 vegetation anywhere in the pond. The Dytiscidse are found in the 

 limited area of the typha beds. 



The species listed are our common species of Laccophilus, Hy- 

 drovatus, Bidessus; Ccelambus incequalis Fabr., dispar Lee, acaroides 

 Lee, and nubihis Lee. ; Hydroporus undulatus Say, dichrous Melsh. 

 and modestus Aube ; Ilybius confusus Aube ; Coptotomus interrogatus 

 Fabr. ; Agabus subfuscatus Shp., and disintegratus Crotch ; Hydaticus 

 piceus Lee, Acilius semisulcatus Aube and fraternus Harr., Dytiscus 



