The Circulatory System of the Box Elder Bug Leptocoris trivittatus (Say)

The dorsal vessel and associated structures in some Heteroptera

“…In the following description, the cardiac chamber is a permanent dilatation of the dorsal vessel, bearing the ostia mid-way along its lateral walls, and the chambered part of the dorsal vessel constitutes the "heart". This is consistent with the description of Nezara by Malouf (1933) and the description of Leptocoris by Wooley (1951).…”

“…This description applies to all the species examined and is in close agreement with that given by Wooley (1951) for Leprocoris. Malouf (1933) two lateral branches arising from the aorta just posterior to the protocerebral lobes of the brain in Nezara; no such accessory vessels were, however, found in any of the specimens examined.…”

“…The first pair of muscles always arises dorsally, sometimes in segment 2 (Eurygaster), segment 3 (Leptopterna), segment 5 (Dysdercus, Heterogaster, Enoplops, Elasmostethus, Dolichonabis, Velia and Gerris) or segment 6 (Triatoma and Phonoctonus). According to Wooley (1951), the first pair in Leptocoris arise from the posterior margin of segment 3, but it appears that he regarded the first apparent abdominal sternite as belong to segment 1, whereas it is here regarded as belonging to the second segment ; hence in Leptocoris the first pair of muscles arise from tergite 4. Posteriorly, the heart is held in position by two caudal muscles or filaments, which may arise from the lateral body wall in segments 8,9 or 10, or may be attached to the rectum.…”

“…(ii) the muscles may consist of interlacing striated fibrillae embedded in the sarcoplasm, as in Aeshna (Zawarzin, 1910), or (iii) of circular and longitudinal fibrillae as described for Nepa by Hamilton (1931). Wooley (1951) claims that the wall of the heart of Leptocoris has the same structure as that of Nepa, but unfortunately his description and illustrations are not entirely consistent. Initially, the present investigation was confined to the histology of the dorsal vessel of Dysdercus, but it soon became apparent that the arrangement of the muscle fibres differed from that described for Leptocoris and Nepa.…”

“…Only six accounts are known to the writer: the heart of Nepa cinerea L. (Nepidae) has been described by Hamilton (1931), that of Lethocerus spp. (Belostommatidae) by Locy (1 884), of Nezaru viridula L. (Pentatomidae) by Malouf (1933), of Cimex Iectularius L. (Cimicidae) by Murray (1914) and of Leptocoris trivittatus (Say) (Rhopalidae) by Wooley (1951). None of these accounts is very satisfactory, and the present study was therefore undertaken to enable a more lucid account of the histology to be given and such aspects as tracheal supply and innervation, which hitherto have been ignored in the Hemiptera, to be considered, and to extend our knowledge of the dorsal vessel to families other than those cited above.…”