150 THE UNIVERSITY SCIENCE BULLETIN. 



Color. Newly laid, pale, grayish green, the outer end of egg blotched 

 with patches of darker color due to a trace of brown. The surface 

 minutely and irregularly hexagonally reticulate, not plainly visible even 

 under low power binocular, but becomes apparent under low power com- 

 pound. A bit of the chorion mounted on a slide and examined by trans- 

 mitted light shows a series of irregular hexagonal figures of various 

 sizes. The boundaries of the figures appearing as a tracery of fine white 

 or transparent lines on a brown ground. The egg clusters are held 

 together and to their support by irregularly globose masses of gelatinous 

 like material. See plate XVII. 



Summary. These giant water bugs, distinguishable by the presence 

 of a groove in fore femora, are fiercely predaceous creatures of our 

 larger ponds. In their nocturnal migrations from one body of water to 

 another they are frequently attracted to the lights. The eggs of L. 

 americanus and of L. uhleri are now known. In nature they are laid on 

 reeds above the surface of the water. Nothing is known about the length 

 of the various stages. 



Genus BENACUS. Stal. 1861. 



There is the one species in this country, B. griseus Say. It is the larg- 

 est of our electric-light bugs. It differs from Lethocenis in having less 

 thickened fore femora which are not grooved to receive the tibiae when 

 flexed. 



The biological notes of any extent (aside from collecting) consist of 

 two papers; one by Brimley, Ent. Netvs, 1905, describing the walking of 

 B. griseus, and the other by Needham, Ent. News, 1907. This second 

 paper is a splendid paper, accompanied by remarkably clear photographs 

 of the egg cluster, hatching eggs, newly" emerged nymph and adult. 



Oviposition. Weed, 1897, tells us eggs are laid in masses on sticks 

 and other rubbish at margin of ponds. Needham, 1907, says that "the 

 egg clusters are two or three inches long, and contain 75 to 100 eggs of 

 a size that for insects is fairly immense. The eggs are attached by one 

 end in more or less regular rows, and they cover in a single layer the 

 broader, flatter side of the stem. They would be conspicuous but for their 

 resemblance in color to the stem." The longitudinal streaking of brown 

 upon a lighter ground, together with the way they are placed and spaced, 

 makes them fall into line with the flutings of the stem, and greatly as- 

 sist in the concealment of the cluster. The egg clusters are attached 

 above the water line. 



The Egg. 

 (Description from Needham.) 



Size. 5 mm. long; 2 mm. in greatest diameter. 



Shape. Oblong oval in form with very obtuse ends. 



Color. Each egg is marked longitudinally with 20 or more irregular 

 stripes of brown (often interrupted, cleft, fenestrate, or anastomosing, 

 and always with uneven margins) convergent toward the center of the 

 free end upon the upper side. Under a lens the eggs remind one of a 

 pile of Georgia watermelons. If the color were green instead of brown 



