IIKMIPTERA. 



I89 



Belostoma americdnum (Fig. 1 59) varies greatly in size. Specimens 

 before me as I write this range from 44 mm. (1.75 in.) to 60 mm. (2.4 

 in.) in length. It is of a pale dirty-brown 

 color, mottled with dark brown ; the ven- 

 tral aspect of the body is speckled with 

 dark brown. The anterior femora are 

 furnished with a groove for the reception 

 of the edge of the tibiae. 



Bendcus griseus can be distinguished 

 from Belostoma by the absence of the 

 femoral groove. In Benacus the ventral 

 aspect of the thorax is marked by five 

 interrupted longitudinal stripes of dark- 

 brown. 



To the genus Zditha belong our more 

 common representatives of the smaller 

 members of this family. The common 

 species of the Eastern United States is 



Zditha flltminca. This measures about FlG - 159— Belostoma americanut 



nine-tenths of an inch in length, and bears 



a round scar on each side of the prothorax (Fig. 160). The 

 females of this species la} - their eggs upon 

 their own backs. These eggs are set upon 

 end, and placed in transverse rows, by means of 

 a long protrusile tube or ovipositor, which the 

 insect can extend far over her own back. The 

 eggs are fastened to the back of the mother by 

 a very thin layer of a waterproof gum secreted by 

 the insect. At about the time when the young 

 brood begins to hatch, the mother sheds the 



Dim- 



Fig. 160. — Zaitha Jlu- 

 minea. 



entire layer of eggs from her back, 

 mock.) 



Family XV. — NatjcoriDjE* 



The Nancoridoe includes flat-bodied, chiefly oval insects, which 

 are of smaller size than the members of the preceding family. The 

 abdomen is without caudal appendages , and the legs are suited for 

 crawling rather than for swimming. The front legs, however, are fitted 

 for grasping, the femora being greatly thickened. There are no 



* Naucoridae, Naucoris : naus (vavi), a boat ; coris (Kopii), a bag. 

 13 



