BR, J. l.Nl. NAI, HIST., 13 2001 



lateral ocelli being closer to the eye margins and the branches of the median fork ai 

 least slightly convergent apically, M, being downturned apically. Most species of the 

 genus, which is rich in species in the tropics, have annulated antennae, which are 

 yellow with each llagcllomcrc brown apically, a character not found in Leia. 



The widespread European species ('. alternans (Winnertz. 1863) i^ now known 

 from southern England and a second species, here described as new, has been found 

 on Jersey, Channel Islands. Although these species are of similar appearance, their 

 genitalia are very different. 



Clastohasis alternans (Winnertz) (Figs 15-17, 21, 23) 



C. alternans has been found at six localities in England north to Yorkshire in 

 recent years, mostly at wooded fen or carr woodland sites with an anomalous record 

 from Buckingham Palace Gardens where the only wetland vegetation is a narrow 

 strip at the margin of the lake. 



This species is predominantly yellow, with dark antennal and abdominal markings 

 (Fig. 23). All flagellomeres are dark apically, this colour occupying progressively 

 more of the length until the last flagellomere is nearly all dark. The abdomen has 

 dark bands on the apical third to half of tergites 1-5, these bands narrowed medially 

 on 1-4 but broadly extended to the base dorsally on tergite 5. with a slight dark 

 patch at the base of tergite 6. The head has a dark patch internal to each lateral 

 ocellus. Genitalia Figs 15-17 (male), 21 (female). The wing length of material 

 examined is 4.2-4.4 mm (male) and 4.4-4.7 mm (female). 



British material of C. alternans 



ENGLAND: Middlesex, Buckingham Palace Gardens. Malaise trap catch till 

 7.vii.l995, 1 male (via C. Plant); Gloucs, Coombe Hill Canal SSSI. 21. v. 1994 (CM. 

 Drake); Cambs, Osier Lake, Godmanchester, late viii.1998. numerous in Salix carr 

 (J.H. Cole); Cambs, Paradise, 19.vii.1998, 1 male (I. Perry); Norfolk, Wheatfen 

 Broad, lO.vii. 1993, 1 male (I. Perry); Yorks, Wheldrake Ings, 17.vii.1996, numerous 

 in hedges by water meadows (Chandler and others, some deposited in NMS). 



Clastobasis loici sp. n. (Figs 18-20, 22) 



Male. Mainly yellow with dark annulations on antenna and dark abdominal 

 markings. Head yellow, more brownish on frons, with a black patch internal to each 

 lateral ocellus. Antenna longer than mesoscutum; yellow with a dark apical marking 

 on each flagellomere, increasing in extent on basal flagellomeres, occupying apical 

 half of flagellomeres 9-13 and apical two thirds of elongate apical flagellomere. 

 Palpus slender, yellow. 



Thorax yellow except for shining brown disc of mediotergite. Thoracic hairs and 

 setae yellowish to brown. Scutum with short yellow hairs on disc, strong marginal, 

 postalar and prescutellar setae; prothorax with strong lateral setae and 4 strong 

 downturned proepisternals; laterotergite with long fine yellow setae: 2 pairs strong 

 scutellars. 



Legs entirely yellow including long slender tibial spurs (1:2:2). Tibia 2 with 6 

 strong anterior setae (becoming anterodorsal on apical half). 5 strong poster- 

 odorsals, a weaker seta basal to each of these series and 2 weak setae in gap between 

 last 2 posterodorsals; several short anteroventrals and posteroventrals and a 

 complete series of shorter posterior setae. Tibia 3 with 8 stronger anterodorsals. with 



