. Blood-sucking mosquitoes of the subtribe Culisetina (Diptera, Culicidae) in world fauna. Mosquitoes. 87 ?^?^/^-'^^?^?. Fig. 50. Short (a) and long (b) siphons in the 4th instar larva of Culiseta bergrothi. near the anterior valve of the stigmatic plate (Fig. 98, d). While measuring, care must be taken to avoid crushing the siphon in the specimen. Otherwise, the results obtained will be unreliable and invalid. To calculate the siphon indices given below we have used the results of measurements using fresh or preserved specimens or even samples with a wax base. Generally, in all Culicinae, the
. Blood-sucking mosquitoes of the subtribe Culisetina (Diptera, Culicidae) in world fauna. Mosquitoes. 87 ?^?^/^-'^^?^?. Fig. 50. Short (a) and long (b) siphons in the 4th instar larva of Culiseta bergrothi. near the anterior valve of the stigmatic plate (Fig. 98, d). While measuring, care must be taken to avoid crushing the siphon in the specimen. Otherwise, the results obtained will be unreliable and invalid. To calculate the siphon indices given below we have used the results of measurements using fresh or preserved specimens or even samples with a wax base. Generally, in all Culicinae, the larvae of filter feeders have a very long* and thin siphon with an index rarely less than 5 while the primary siphon index in the larvae of periphytophages is usually much less than 4, decreasing in some cases (Allotheobaldia longia- reolata) to or less. Marshall's report (1938, Table XI, p. 105) that the siphon index for Culiseta fumipennis varies from to is clearly an underestimation. In the figures in his own work (Fig. 61, p. 90 and Fig. 137, p. 224), the relative length of the siphon in C. fumipennis differs little from that of ? morsitans (Fig. 138, p. 228) and is close to 5; the works of Rioux (1958) and Senevet and Anda- relli (1959a) present similar data. In all Culisetina, the variation range of the primary siphon index of larvae is much greater (Maslov, 1952, 1963 and others). The illustrations given (Fig. 50) confirm this variation in the example of C. bergrothi in which the range between the extreme values of the primary siphon index () attains, as in C. alaskaensis, a record figure of 100%. Such a wide variation is , *The larvae have a long siphon capable of holding a large volume of water without withdrawing from the substratum (or the water surface); herein lies the advantage of the long siphon in the filter feeders (Maslov, 1952, 1961a, 1963 and Monchadskii, 1937).. Please note that these images are extracted from scanned page images that ma
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