THE LOCATION OF CONTACT CHEMORECEPTORS SENSITIVE TO SUCROSE SOLUTIONS IN ADULT TRICHOPTERA 1 HUBERT FRINGS AND MABLE FRINGS Department of Zoology and Entomology, The Pennsylvania State University, University Park, Pennsylvania, and Alt. Desert Island Biological Laboratory, Salisbury Cove, Maine Descriptions of the mouth-parts and feeding of adult Trichoptera in recent American text books and other general works on entomology are not consistent. Folsom and Wardle (1934, pp. 20, 39), Frost (1942. p. 89), Comstock, (1950, p. 555), Metcalf, Flint and Metcalf ( 1951, p. 229) and Ross ( 1948. p. 367) described the mouth-parts as "vestigial," "rudimentary," "suhatrophied," or "greatly re-duced." These views carried as a corollary the belief that the adults take little or no nourishment, and Brues (1946, p. 44) listed caddis-flies with the "aphagia" : in-sects "which do not feed at all after maturity." Borror and DeLong (1955, p. 437), however, described the mouth-parts as "chewing type, with the palpi well developed but with the mandibles much reduced," and stated that "the adults feed principally on liquid foods." Swain (1948, p. 79) also stated that adult caddis-flies take liquid food, but termed the mouth-parts a "short, uncoiled proboscis." A review of earlier accounts reveals a similar lack of agreement. Reaumur ( 1737, pp. 175-176) wrote that the mouth-parts of Trichoptera are for sucking and lapping, like those of Diptera. Kirby and Spence (1826, p. 464, PI. VII, Fig. 1), on the other hand, regarded the mouth-parts as modified mandibulate. Burmeister ( 1832, pp. 68 ; 377-378) stated that the mouth-parts are intermediate between the mandibu-late and haustellate types, comparing them with those of bees. Lucas ( 1893) made a detailed study of the mouth-parts of Anabolia }urcata( --laci'is). He found the mandibles to be atrophied, the labrum and maxillae reduced, and the labium devel-oped into a sucking organ, the haustellum. Ulmer (1904) and Cummings (1913, 1914) reported a well developed haustellum to be present in every family of Tri-choptera. These facts are reported in the special works on Trichoptera by Betten (1934, pp. 19-22). Ross ( 1<>44. p. 4) and Mosely and Kimmins (1953, pp. 10-11), and in the text books of Packard ( 189S. pp. 74-75 ). Weber ( 1933, pp. 66-68 ; 1954. pp. 297-298 ), and Imms (1948, pp. 19, 411-412). Reaumur (1737, pp. 175-176) stated that adult Trichoptera take liquid foods, and Burmeister (1832, pp. 377-378) reaffirmed this, reporting that he found them feeding on nectar of flowers. Lucas (1893) reported finding tiny particles like pollen in the folds of the haustellum. and he therefore believed that they feed on nec-tar. There were other workers who made observations, often quite casual, that confirmed or contradicted these ideas. These are reviewed in the papers of Siltala (1907) and Dohler (1914). Siltala (1907) gave adult Pliryc/anea striata and Limnephilus rJwuibicus only water for three or four days, then placed a flowering 1 Paper No. 2048 in the Journal Series of the Pennsylvania Agricultural Experiment Sta-tion ; supported in part by Research Grant No. E-802 from the National Microbiological In-stitute of the National Institutes of Health, Public Health Service. 92
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