RECENT LITERATURE. 135 



have passed in their evolution from land-bugs, originally probably 

 from some form similar in structure and appearance to Acanthia, 

 Fabr., Latr. The genera admitted are : — 



1. MoNONYX, Lap. = Phintius, Stal, with 18 spp. (7 new). 



2. Matinus, Stal, with 5 spp. (3 new). 



3. Peltopterus, Guer. = ScylcBcus, Stal, with 3 spp. (2 new). 

 Mononyx has a very wide distribution, seven species occurring in 



America, five each from the Oriental and Australian regions, and one 

 from the Ethiopian ; the other genera are much restricted, Matinus 

 being entirely Australian, while Peltopterus is insular, having been 

 recorded only from the Philippines, North Borneo, Salomons, Mari- 

 annes, Mauritius, and a few smaller islands. The genus Nerthra, Say, 

 from America, remains unknown. 



The value of Dr. Montandon's precise and uniform descriptions is 

 greatly enhanced by the synoptic tables, in which structural characters 

 are employed for the preliminary differentiation of the species ; but 

 there are unfortunately no figures, a want which cannot always be 

 supplied even by the most careful and detailed descriptions. 



________ G. W. K. 



Slater, F. W. The Egg-carrying Habit of Zaitha. (' The American 

 Naturalist,' 1899, xxxiii. pp. 931-3.) 



It has been long known that certain American waterbugs of the 

 family Belostomatidge, particularly Zaitha flmninea, Say, and Deino- 

 stoma (= Serphus) dilatatum, Say, have the habit of carrying their eggs 

 on their back until they are hatched, and it has always been taken for 

 granted that the female is the egg-carrier. Miss Slater, however, has 

 made a study of the sexual organs of Zaitha, and finds that everyone 

 of the egg-carrying individuals which she has dissected is a male, and 

 that the ovipositor of the female is so short that it would be impossible 

 for her to reach her own back with it. 



The ovipositing season lasts from June to the end of August, and 

 the eggs, which are comparatively of large size, number from seventy- 

 five to eighty-five, " placed in regular diagonal rows on the upper side 

 of the wings of the male." The male is an unwilling porter, and is 

 captured by the larger female and compelled to endure the indignity, 

 after a series of well-contested combats. "That the male chafes under 

 the burden is unmistakable; in fact, my suspicions as to the sex of the 

 egg-carrier were first aroused by watching one in an aquarium, which 

 was trying to free itself from its load of eggs, an exhibition of a lack 

 of maternal interest not to be expected in a female carrying her own 

 eggs. . . . For five hours I watched a silent unremitting struggle 

 between the male and the female. Her desire was evidently to capture 

 him uninjured. She crept quietly to within a few inches of him, and 

 there remained immovable for half an hour. Suddenly she sprang 

 towards him ; but he was on the look-out, and fought so vigorously 

 that she was obliged to retreat. After this repulse she swam about 

 carelessly for a time, as if searching for food was her only thought. 

 But in ten or fifteen minutes she was back in her first position in front 

 of him. Again there was the attack, and again the repulse. The 

 same tactics were continued until midnight, when, despairing of her 



