FAMILY DYTICIDjE. 55 



2. The Gyrinid^ are provided with short clavate antennae : body oval and convex, as 

 in the Dvticid^ but more glossy. The legs are unequal in this family : the anterior ones 

 are long, and the four posterior are short, compressed, and formed for swimming. The 

 larvse diflTer also from those of the Dyticidje, by having on each side of the fourth and 

 seven following segments a membranous conical appendage, which is flexible and bearded 

 at the sides : these appendages are subordinate to the respiratory organs, with which they 

 eommunicrfte by a small tube. 



Dyticidse. 



Halipides. 



Jlntennse ten-jointed ; posterior coxje dilated into a large shield, covering the base of the 

 1^. 



Genus HALIPLUS (Clairv.). Cnemidotus (HL). 

 Maxillary palpi with the last joint very minute and subulate. 



Haliplus 12-punctatus. (Plate xx, fig. 15.) 



Head, thorax and elytra buff-colored. Elytra with twelve black spots, some of which are 

 confluent ; inner margin and anal extremely black ; thorax with a lunate black or 

 brown spot on its anterior margin ; eyes black. 



Haliplus immaculaticollis. (Plate xx, fig. 16.) 



Insect buff-color : elytra with ten black spots, the central comparatively large, and com- 

 mon to both elytra ; thorax brown, immaculate. 



Gekus DYTICUS. Dytiscus (Linn.) 



^ Anterior male tarsi patellated ; claws didactyle ; maxillary palpi with the second and 

 third joints equal ' (Wkstwood). 



Dyticus harrisii. ( Plate V, fig. 10.) 



Color black softened into olive ; front or forehead hiteous ; lateral margins of the thorax 



luteous : upon the latter it diminishes posteriorly, and extends to the under side of 



the same ; beneath, the thorax and first pair of legs are luteous : posterior legs long, 



and furnished with two dense rows of brown cilia. Length one inch. 



This species is rather common in small ponds of water, where the bottom is clear and 



sandy : a locality where it may always be found, is at the head springs which supply the 



eity of Albany with water. 



