188 ZOOLO&Y. 



attains a length of thres incli33, and is sufScientlj strong to kill small Hsh 

 and frogs. Dr. Jo3e[)li Leidy has given the anatomy and characters ot 

 several i^orth American species in t'le Jonrnal Acad. Nat. Sci. 



Fam. 10. GiOguUdiM. Gahjulus ooidafus is a small iS"orth American 

 insect, with an oval, depressed form, a l)road 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 tiie power of leaping a few inches, although 

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

 endeavor to escape by flight, 



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

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

 ITijdrometra moves rather slowly 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 Tlydrometra. ^T\\e larva of this genus 

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

 sponding oceanic genus Halohates., it sustains Professor Agassiz's view that 

 freshwater forms are higher than marine ones. Ilalobates being rarely 

 found with the wings developed, Westwood thinks they are not to be 

 considered as imagos, especially as the abdomen is small ; bat 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 a,hy. 



Fam. 12. Lepfopidce. 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 AcantMa by 

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

 This family is named Rlparii by Burmeister. 



Fam. 13. Redainid'.p. This family includes active predaceous species 

 with a short, stout I'ostrum, 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 Ar'ilus novenaruts, 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. Tinrpdcp. The species of Tingts 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 tlie larvae 

 do not move from their first station. Sijrtis is also very torpid in its 

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

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

 first separated from the Linnrean genus C'unex 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 Cimex, and on this account they 

 392 



