AQUATIC HEMIPTERA. A STUDY IN THE RELATION 

 OF STRUCTURE TO ENVIRONMENT. 



By J. R. DE LA ToRRE-BuENO, White Plains, N. Y. 



Water is everywhere. Wherever there is water, there are 

 to be found Aquatic Hemiptera. From the woodland spring 

 deep in the cool and dusky shadows to the tropic ocean steaming 

 in the flaming rays of the noonday sun, these daring insect 

 navigators adventure themselves on the bosom of the waters, 

 to them as vast as, even vaster than the mighty seas were to the 

 bold mariners of old. Protean in form, variable in size — ^some 

 less than the head of a pin, others of monster size for insects, 

 for they attain the length of half a foot — these fierce pirates 

 range the waters, seeking prey. Not even the wide-spread 

 and multiform water beetles exhibit such a wide diversity of 

 form, structure and habitat. 



The old-time divisions of Cryptocerata and Gymnocerata 

 Littoralia separate these two Hemipterous groups on the 

 obvious character of the absence or presence of visible, free 

 antennae, and very fairly divide the dwellers in the waters from 

 those that live upon them or on their shores. And in this 

 antennal diversity we have indeed a character arising strictly 

 from the conditioning environment. Obviously, long antennas, 

 while of the utmost use to the above-water forms, would be 

 distinctly in the way in deep-swimming insects, so in the Order 

 Sandaliorrhyncha, containing the family CorixidcB, and in the 

 Heteropterous families NotonectidcB, Naucoridce, Belostomatidce 

 and NepidcB, the antennae are three or four-jointed, concealed 

 in foveae under the head, the joints being sometimes palmately 

 explanate, as in Lethocerus; sometimes stout and simple, with 

 fringing hairs, , as in Notonecta. But the nymphal development 

 of Belostoma and Ranatra, for example, points to the simple, 

 stout, three- or four-jointed antenna as the primitive form, 

 since in the early stages of these bugs they are simple and do 

 not begin to show the explanations until the third or fourth 

 instar. 



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