436 The University Science Bulletin. 



were collected in that region. The possibility of his R. fusca not 

 being known to us in nature seems to me quite remote. 



According to the figure, Ranatra fusca of Palisot de Beauvois is 

 a large, robust insect with broad anterior femora and short legs and 

 respiratory tube. The cjuestion is, what insect of the range indi- 

 cated has these characters? After careful consideration of the 

 problem I must conclude that the only one with the proper size, 

 robustness, broad femora and short legs is Ranatra americana 

 Montd. It has the variable respiratory tube, usually longer than 

 Palisot's figure, but not uncommonly as short, and in every case 

 shorter than the body. The failure of the artist to indicate any 

 apical tooth on the anterior femur is readily understood, since we 

 know that this character is often obscured by a marginal fringe of 

 pile so completely as to escape any but the closest scrutiny. It is 

 indeed a somewhat variable structure; in some examples much re- 

 duced, and in others plainly visible. The writer has in his collection 

 specimens which fit Palisot's figure almost exactly. 



The second species with which we are concerned is Ranatra nigra 

 H. S. This species was described in 1853 from America by Herrich 

 Schaffer in his "Die Wanzenartigen Insecten." It was described as 

 being from 2 to 21/8 inches long from beak to tip of respiratory 

 tubes, with the respiratory tubes not much over half as long as the 

 body; indeed, he says they were three-fourths of an inch! Now the 

 only species we have which in a series of specimens has a respiratory 

 tube averaging three-fourths of an inch long is R. protensa Montd. 

 Doctor Montandon described his R. protensa from a single large 

 female, which, because of its very yellowish color and shorter limbs, 

 did not suggest R. nigra to his mind. Indeed, considered alone, it is 

 not at all to be expected that it would. R. nigra was described as 

 having the structure of thorax and relative length of limbs as in i?. 

 elongata. Now, R. elongata has very elongate hind femora, the tips 

 surpassing the last abdominal suture by a considerable distance. 

 The length of limb in R. protensa Montd. is, on the whole, not as 

 great as in R. elongata, but is strikingly longer than in R. linearis 

 L., with which he compared it in size, and this suggested R. elongata. 

 Indeed in many specimens of R. protensa Montd. the hind femora 

 surpass the last abdominal suture. The front legs of R. protensa 

 are long and very slender and the thorax is more like that of R. 

 elongata than of R. linearis. Doctor Montandon said that he had 

 never seen any specimens from North America with legs as in 

 elongata. We have three species with limbs relatively as long. 



