142 THE UNIVERSITY SCIENCE BULLETIN. 



Key to Genera — Concluded: 



B. First (basal segment of the beiak longer than the second; 

 furrow of the wing membrane nearly or quite straight. (Size 

 about 1 inch or less.) Belostoma. 



BB. First segment of the beak shorter than the second. Furrow of 

 the wing membrane shallowly S-shaped. (Size more than 1^/^ 

 inches.) 

 r C. Anterior femora grooved for the reception of the tibiae. 



Lethocei'us. 

 CC. Anterior femora not grooved for the reception of the 

 tibiae. Benactis. 



The keys to species and their descriptions are omitted for the present, 

 as the writer is aware that Mr. J. R. de la Torre Bueno has been work- 

 ing upon this group for the past few years, and has promised us a paper 

 shortly. 



B. Biology of the Belostomatid. 



General Notes. The Belostomids, because of their large size and their 

 frequency about electric lights, have been frequently noticed by the lay- 

 man. With the installation of electric lights in a town, there usually 

 come inquiries regarding these giant bugs. The bugs are sent in with 

 the statement that they have never before been in that part of the 

 country. On the other hand, they have been there, but have not been 

 drawn to the attention of the populace. As an indication of the general 

 interest taken in these bugs note the numerous references to be found in 

 the AmericaJi Naturalist of earlier years. This periodical was at one 

 time of general interest to all biologists and reflected very well matters 

 of general note. 



Another interest that is attached to these insects is the fact that in 

 two of the four genera, Belostoma and Abedus, the males carry the eggs 

 about with them. 



All of these bugs live in the water, where they rest as a rule, clinging 

 to some support with the tip of the abdomen in contact with the surface 

 film. All are fiercely predaceous. 



Genus ABEDUS Stal. 



There are five species of this genus listed for America north of 

 Mexico, by Van Duzee. A. ovatus, A. breviceps, A. dilatatus, A. macronyx, 

 and A. indentatus. This genus is confined to our southwest — Arizona, 

 New Mexico, Texas and California. Aside from the collecting habitat 

 notes, little has been done on their biology. The eggs are carried upon 

 the back as in Belostoma, as evidenced by material in our collections. 

 Uhler mentions this fact under his discussion of Serphiis in Cambridge 

 Natural History. The fierce predaceous tendencies of Abedus macronyx 

 have been noted by Harvey under the title, "A Ferocious Water Bug." 

 Here he says that the bug is to be found in the warmer streams and 

 ponds of California. Children who wade in these waters have named it 

 "toe pincher." He placed one in an aquarium and its depredations were 

 astonishing. It devoured a 3-inch trout, young frogs, tadpoles, snails, 

 and various smaller fry. He then isolated it and found it would devour 



