188 ZOOLOGY. 



attains a length of thre3 inchsi, and is sufficiently strong to kill small lish 

 and frogs. Dr. Joseph Lsidj has given the anatomy and characters oi 

 several North American species in the Journal Acad. Nat. Sci. 



Fam. 10. Gdcjidide. Galgulm oculatm is a small North American 

 insect, with an oval, depressed form, a broad head, and pedunculated lateral 

 eyes. It may be seen during the day running along the grassy and sandy 

 shores of rivers, but it is not aquatic, although it can swim to the shore if 

 thrown into the water. It has the power of leaping a few inches, altliough 

 the feet do not present saltatorial characters. When pursued they do not 

 endeavor to escape by flight. 



Fam. 11. TIijdwmetridcB. The members of this family live upon the 

 surfiice of the water, over which some of them move with great rapidity. 

 ILjdrometra moves rather slowdy over the surface, with the body elevated 

 above it. The ordinary boat-shaped species, with four of the feet adapted 

 to locomotion, belong to the genus Ilydrometra. The larva of this genus 

 has the abdomen very small, and as this is a characteristic of the corre- 

 sponding oceanic genus Ilcdobates^ it sustains Professor Agassiz's view that 

 freshwater forms are higher than marine ones, ITcdMhates being rarely 

 found with the wings developed, AV"estwood thinks they are not to be 

 considered as imagos, especially as the abdomen is small ; but an extension 

 of the views of Agassiz affords a more satisfactory explanation. Many 

 individuals of Gerris^ which seem to be perfect, are without wings, and 

 seem never to acquire any, 



Fam. 12. LeptopidiJi. This is a small family with the body oval and 

 depressed, the eyes large, the feet slender, and the rostrum long. These 

 insects are small and active, running and flying along the margins of 

 water. The principal genus is Salda., improperly named Acanthia by 

 Latreille, a name used previously bv Fabricius for the Cimex lectidarius. 

 This family is named Rlparii by Burmeister. 



Fam.. 13. Redaviidiv. This family includes active predaceous species 

 with a short, stout rostrum, sufficiently strong to pierce insects with a 

 tolerably hard integument. The head is narrow behind, forming a kind of 

 neck, the eyes are prominent, and there are two stemmata. The North 

 American Arilus novenarius., Say, Am. Ent., has the pronotum arched 

 above, and notched like the cogs of a small wheel. The puncture of these 

 insects is somewhat poisonous, 



Fam. 14, Tingidcv. The species of Tingis have a small body with tlie 

 wings strongly reticulated, and a membranous expansion upon each side 

 of the prothorax. They move very slowly, and are found upon leaves, the 

 juices of which they suck in all their stages. It is probable that the larvna 

 do not move from their first station. Si/His is also very torpid in its 

 movements ; it lives upon trees, and probably feeds upon insects, as the 

 anterior feet are very stout, and apparently raptorial. The genus Acanthia., 

 first separated from the Linnsean genus Cimex by Fabricius, includes the 

 bedbug, Acanthia Uctularia {pi. 80, fig. 67). Amyot and Serville state 

 that the name Acanthia.^ Fabr., 1776, must stand, being the first given after 

 the dismemberment of the old genus Chnex^ and on this account they 

 392 



