92 THE UNIVERSITY SCIENCE BULLETIN. 



Hydrometra martini Kirk. 1900. 



Kirkaldy, Ento., XXVIII, p. 175, 1900. (New name for lineata Say.) 



"Fuscous, hemelytra dull whitish with black nervures. Inhabits 

 U. S. Body fuscous or brown, more or less deep; hemelytra dull 

 whitish or dusky, with black nervures; tergum pale, quadrilineate with 

 black; two of the lines on the edge and interval between the two inner 

 lines, dull whitish or bright yellow; the incisures of the segments more 

 or less black; beneath and feet obscure yellowish; thorax with a more 

 or less obvious pale line; length seven-twentieths of an inch. This is 

 very much like the stagnorum F., but the hemelytra are not testaceous 

 and there is no thoracic impressed line (male). Body blue-black; thorax 

 with a pale line; antennae and feet dark honey yellow; tergum and venter 

 without lines." — Say. 



Disti'ibution : Ontario, Maine, New York, New Jersey, Pennsylvania, 

 Maryland, District of Columbia, North Carolina, Florida, Indiana, Illi- 

 nois, Louisiana, Texas, Arizona, and Kansas. 



Martin, 1900, pointed out genital differences between H. lineata {H. 

 martini Kirk), which he reared, and the European H. stagnorum. The 

 terminal segment of the male of H. martini as seen from above is 

 abruptly swollen toward the tip, which is truncate. It bears a prominent 

 spiniferous tubercle which arises shortly before the tip. The lateral 

 caudal margin of this segment is sinuate. 



Hydrometra australis Say. 1832. 



Say, Heter. N. Harm, p. 35, 1832. 



"Head beyond the eyes, a little longer and a little more dilated at 

 tip than H. martini Kirk. Second joint of the antennae a little more 

 dilated at tip. Abdomen with five lateral whitish points. Inhabits 

 New Orleans;" after Say. Bueno, 1905, points out that the genital 

 characters raise Say's variety to a species rank, the male terminal 

 segment as seen from above being swollen, but not abruptly so and 

 bearing a small tubercle if any, while the lateral margin is straight, 

 not sinuate as in H. martini Kirk. On plate XIII are figures of the male 

 genitalia of both species, taken from Bueno. 



Found in Georgia, Florida, and Louisiana. 



B, Biology of Hydrometra. 



General notes. A few early notes on the behavior of this bug have 

 been mentioned. These dealt with their habitat and feeding habits. 

 In 1895 Arrows, in Science Gossip, gave an account of the habits of 

 Hydrometra stagnorum. This was followed in 1899 by two papers, one 

 on the mating, by Palumba, and the other by Kirkaldy in his "Guide to 

 the Study of British Water Bugs." As for our own American species 

 we have Martini's interesting paper, which appeared in Canadian Ento- 

 mologist for March, 1900, and Bueno's notes in 1905 (Can. Ent.). O. 

 Heidemann, in the Journal N. Y. Ent. Soc. for the same year, mentions 

 the number of generations and developmental period. 



Biology of H. martini Kirk. 

 Habitat. Uhler said that "it sometimes lives in the dirty holes, 

 among the duckweeds, Lemna, where it wanders about over the green 



