178 Annals Entomological Society of America [Vol. XIII, 



limited space it is possible to make only a few generalizations. 

 A precaution may well be taken with regard to the use of the 

 word "adaptation." In the minds of some of the modern 

 biologists it is not orthodox to even mention this word. There- 

 fore this word will not be used, but attention is called to the 

 fact that the insects of this vast group are fitted into the 

 environment wherever they will fit, with the result that certain 

 type forms, together with certain biological characteristics, are 

 to be found in the different types of environment. 



There is a considerable group of aquatic beetles. Some of 

 the larvae crawl about over the submerged Vegetation and 

 resemble some of the neuropteroid larvae of the' same habitat 

 as much as they do other closely related Coleoptera. In the 

 swift water of a lotic envirorimeUt the limpet-like larva of 

 Sphenus is to be found. ■ • ■ • 



A large group of beetles typified by the Carabidse is found on 

 the ground and under its cover of debris. The campodiform 

 type of these larvae has already been referred to and it is to be 

 noted that this same type form is to be found among all surface 

 feeding larvae whether they feed upon the ground as the Cara- 

 bidae do or whether they are slightly modified for feeding upon 

 the surface of plants as the Chrysomelidae and Coccinellidas 

 do. These type forms, however, are characteristic of the 

 families only in so far as the species retain the typical habits 

 of the families. The family Chrysomelidae has certain members 

 which feed upon aquatic plants and these species have departed 

 from the family type and have taken on various specializations 

 leading to a virtual apodiform condition in some species. 



Another great group of beetles passes the larval life within 

 the nutrient medium. Some of these make their way through 

 a hard substance with a great deal of effort and are typically 

 apodiform. They are highly specialized for this mode of life 

 and are helpless upon an exposed surface. Others which are 

 normally found in softer substances may have well developed 

 thoracic legs, as in cases where it is necessary for the larvae to 

 pass through a large amount of substance in order to accumulate 

 enough nutrient material for maintenance and growth. Still 

 •others which live in a soft medium of high nutrient value may 

 have limited means of locomotion and the entire larval life 

 may be spent in a very limited space. 



