366 



AN INTRODUCTION TO ENTOMOLOGY 



Fig. 419. — Lethocertis america- 

 nus. 



The members of this family are all wide and flat-bodied aquatic 

 insects, of more or less ovate outline. The fore legs are raptorial ; 

 the middle and hind legs are fitted for 

 swimming, being flattened and ciliated; 

 this is especially true of the hind legs. 

 At the caudal end of the body there is, 

 in the adult, a pair of narrow, strap-like 

 respiratory appendages, which are re- 

 tractile. 



These insects are rapacious creatures, 

 feeding on other insects, snails, and small 

 fish. Like other water-bugs, they fly from 

 pond to pond and are frequently attracted 

 to lights. This is especially the case where 

 electric lights are used, into which they 

 sometimes fly and are killed by hundreds. 

 On this account they are known in many 

 parts of the country as "electric-light 

 bugs." 



The family Belostomatidae is repre- 

 sented in this country by four genera. 

 Recent studies of the nomenclature of the 

 genera of this family have resulted in the 

 making of changes in some of the generic 



names. This should be kept in mind when using the older text-books. 

 Our genera are separated by Hungerford ('19) as follows: 

 A. Mesothorax with a strong midventral keel; membrane of the hemelytra re- 

 duced Abedus 



AA. Mesothorax without a midventral keel; membrane of the hemelytra not 

 reduced. 



B. Basal segment of the beak longer than the second; base of the wing- 

 membrane nearly or quite straight. Body about 25 mm. or less in 

 length Belostoma 



BB. Basal segment of the beak shorter than the second; base of the wing- 

 membrane sinuous. Body more than 37 mm. in length. 

 C. Anterior femora grooved for the reception of the tibia. ..Lethocerus 

 CC. Anterior femora not grooved for the reception of the tibia.. Benacus 



Lethocerus. —To this genus 

 and the following one belong our 

 larger members of this family. 

 The appearance of these insects 

 is indicated by Figure 419, which 

 represents Lethocerus americdnus. 

 In this genus the anterior femora 

 are furnished with a groove for 

 the reception of the tibia. Five 

 species have been described from 

 the United States and Canada. 

 In most of the references to these 

 Fig. 420. — Belos- insects in our literature the gener- 



toma fluminea. ic xisxaQ Belostoma is used. pjg ^21. Male of 



Benacus. — Only a single spe- Abedus, with eggs. 



