Immatures of Palaearctic species of the weevil genus Tychius (Coleoptera, Curculionidae): new descriptions and new bionomic data with an evaluation of their value in a phylogenetic reconstruction of the genus Author Skuhrovec, Jiří Author Gosik, Rafał Author Caldara, Roberto text Zootaxa 2014 2014-07-23 3839 1 1 83 journal article 5426 10.11646/zootaxa.3839.1.1 6d32f9c2-3094-425b-bb7e-9c6e0517d4fd 1175-5326 4927721 AA7FEED5-5C1F-48D0-A172-5C25C4001DF3 Tychius (s. str.) decretus Tournier 1874 Caldara 1990: 193 . Material examined . 1 larva from pods of Trifolium resupinatum L. collected 28.v.1979 at Posada , Nuoro province , Sardinia ( Italy ), leg. R . Caldara , and 8 pupae reared from larvae collected contemporaneously together with the others, all determined by association with reared adults. Differential diagnosis. See Tables 2 and 3 . Description of mature larva. COLORATION. Head brown or dark yellow. All thoracic and abdominal segments light yellow. HEAD CAPSULE AND MOUTH PARTS. Head width: 0.38 mm (see Table. 1 ). Endocarinal line present, reaching middle of frons. Des 1 located very near frontal suture; des 2 located mediolaterally; des 3 located along frontal suture; des 4 very short located along frontal suture; des 5 located anterolaterally; des 4 7 times shorter than des 3 and des 5 ( Fig. 164 ). Fs 1 and fs 2 absent; fs 3 short, located medially; fs 4 located anteromedially (along epistoma); fs 5 located anterolaterally (along epistoma), 4 times longer than fs 3 ( Fig. 164 ). Les distinctly shorter than des 3 . Ves short. Postepicranial area with group of 4 minute pes . Antennal segment membranous, bearing conical sensorium and without sensillum ( Fig. 167 ). Labrum ( Fig. 168 ) approximately 2 times as wide as long; lms 1 4–5 times shorter than lms 2 , lms 3 some shorter than lms 2 ; anterior margin doubly sinuate. Clypeus ( Fig. 168 ) 2 times as wide as long; with 1 short cls located posterolaterally; anterior margin slightly rounded. Epipharynx ( Fig. 169 ) with 2 pairs of als , different in length; with 2 pairs of short and triangular ams ; with 2 pairs of relatively short and finger-like mes ; labral rods relatively long, elongate, strongly converging posteriorly. Mandibles ( Fig. 166 ) with 2 short mds , different in length. Maxilla ( Fig. 165 ): stipes with 1 stps , 2 pfs of different length, pfs 1 distinctly shorter than pfs 2 , and 1 mbs , distinctly shorter than pfs 2 , and 2 sensilla; mala with 4 straight dms , different in length; with 3 vms , short and almost of equal length. Maxillary palpi: length ratio of basal and distal palpomeres 1:1; basal palpomera with 1 short mpxs ; distal palpomera with group of 4 conical, cuticular apical processes. Prementum ( Fig. 165 ) heart-shaped, with 1 prms ; margin of ligula rounded, ligula with 1 lig ; premental sclerite distinct. Postmentum ( Fig. 165 ) with 3 pairs of pms , almost of equal length. THORAX AND ABDOMEN. Body length 1.8 mm (see Table. 1 ), moderately elongate. Abdominal segments I–III slightly smaller than abdominal segments IV–VI ( Fig. 170 ). Spiracles on abdomen in anteromedian parts of segments (abdominal seg. I–VIII). Chaetotaxy of body rather reduced. Setae moderately short or very short and light yellow. Thorax. Prothorax ( Fig. 171 ) with 6 prn ; all macrosetae of equal length; 1 moderately long ps ; 1 eus . Meso- and metathorax ( Fig. 171 ) with 1 prs ; 2 pds , almost of same length; 1 ss ; 1 eps ; 1 ps ; and 1 short eus . Each pedal area of thoracic segments well-separated and with 2 pda . Abdomen. Abdominal segments I–VII ( Fig. 172 ) with 1 prs ; 2 pds of different length; 3 very short ss ; 1 eps ; 1 ps ; 1 lsts ; and 2 short eus . Abdominal segment VIII ( Fig. 173 ) with 1 prs ; 2 pds ; 3 very short ss ; 1 eps ; 1 ps ; 1 lsts ; and 2 short eus . Abdominal segment IX ( Fig. 173 ) with 1 ds ; 1 ps ; and 1 sts . Anal lobes on abdominal segment X ( Fig. 173 ) with 1 very short, feebly visible seta. Description of pupa. COLORATION. Body whitish yellow. MORPHOLOGY ( Figs. 174–176 ). Body length 1.4–2.4 mm ; widest part 0.6–1.1 mm (see Table. 1 ). Body elongate. Rostrum very long, approximately 7 times as long as wide, almost reaching metacoxae. Pronotum 1.4 times as wide as long. CHAETOTAXY ( Figs. 174–176 ). Setae distinct, short, unequal in length, light brown; on pronotum and head placed on small protuberances. Head capsule including 1 vs , 1 os , and 1 pas . Rostrum without setae. Vs and os as long as setae on pronotum, distinctly longer than pas . Pronotum with 2 as , 2 ls , 1 ds , and 1 pls ; ds distinctly smaller than other setae on pronotum. Dorsal parts of meso- and metathorax with 1 seta. Each apex of femora with 2 fes . Setae on abdominal segments I–VIII placed medially and laterally; all abdominal setae located on small, conical protuberances. Pseudocerci very short, slightly curved inside. Biological observations. Pupae were found in the cell 7 days later the larvae entered the soil. The duration of the pupal stage was 12 days. Adults were found walking on the surface 3 days later. Remarks. The same pods, where larvae of T. decretus were collected, were more extensively parasitized also by larvae of Apion trifolii (Linnaeus, 1758) . In the same field the closely related species T. pusillus was also collected, but living on Trifolium resupinatum (see above).