132 A. WATSON 



There is apparently less individual variation in tetrathyra than in the other two 

 species of this species-group. 



Material examined. Type. The type material of this species is lost. A 

 thorough search by Dr. P. Viette in the Museum national d'Histoire naturelle and by 

 myself and my colleagues in the collections of the British Museum (Natural History), 

 in one of which museums the original material was probably deposited, has failed to 

 reveal any of the material of tetrathyra examined by Mabille. Because of the close 

 similarity between tetrathyra and the two other species of the species-group it is 

 necessary to designate a neotype for tetrathyra. The above description is based on 

 a series of ten males (originally in the Rothschild collection) from Diego Suarez in 

 northern Madagascar ; they closely match the original description and are probably 

 correctly identified as tetrathyra. Neither the sex nor the exact source of Mabille's 

 material are known accurately as no details other than " Madagascar " accompany 

 the original description. I have selected one of the ten males as the NEOTYPE. 

 It bears the following data : " Diego Suarez, 8 March 1917 (G. Melou) ; Rothschild 

 bequest B.M. 1939-1 ; Photographed B.M. negative No. 31063 ; Drepanidae 

 genitalia slide No. 608 ; Crocinis tetrathyra (Mabille), det. A. Watson 1963, Neotype " 

 (data from each label separated by a semi-colon) . 



Other material. British Museum {Natural History). N. Madagascar: 9 $, 

 Diego Suarez, i,vii.i9i7 {Melon). 



ISOSPIDIA gen. n. 



(Gender : feminine) 

 (Text-figs. 219-227 ; PI. 14, figs. 326-330 ; Map 6) 



Type-species : Oreta angustipennis Warren, 1904. 



Description. $, $. Proboscis vestigial ; palp extending to just above labrum, with vesti- 

 ture of elongate scales on ventral or anterior surface ; antennae closely lamellate, each lamella 

 touching adjacent lamellae only at its base and apex. 



Meso- and meta thoracic tibia each with one pair of terminal spurs. Costa of fore wing nearly 

 straight except at base and apex ; apex distinctly falcate ; outer margin straight or slightly 

 convex. Outer margin of hind wing evenly rounded. Fore wing venation : R 1 arising from 

 close to end of cell or on short stalk with i? 2 + 3 ; R2 + 3 an d ^4+5 closely apposed, sometimes on 

 short stalk from cell, separating into their elements near apex without forming areole or with i? 4 

 anastomosing at a point or for short distance with R 3 to form areole. Sc + R 1 anastomoses with 

 Rs for short distance distal to end of cell in hind wing. Antemedial fascia of upper surface of 

 fore wing present in brunneola, absent in angustipennis ; conspicuous discocellular spot and in a 

 few specimens a weakly marked posterior cell-spot ; well marked oblique postmedial fascia. 

 Upper surface of hind wing with well-marked antemedial fascia continuous with postmedial fascia 

 of fore wing ; otherwise unmarked. Upper surface of hind wing unmarked, but fore wing either 

 with trace of upper surface pattern or as strongly marked as upper surface. (See Plate 14.) 



genitalia. $ : uncus clothed with long setae, shielded ventrally by a pair of acuminate 

 arms ; vinculum approximately "8"-shaped ; valve attenuate, apically acuminate ; aedeagus 

 with stout, spinose, apical process ; eighth abdominal sternum and tergum modified to form part 

 of genitalia, posterior margin of each emarginate or concave, anterior apodemes well developed. 

 $ : eighth segment considerably modified and heavily sclerotized dorsally and laterally ; 

 two pairs of setose ovipositor lobes ; signum a pair of spinose, invaginate, hemispherical cups 

 {angustipennis) or a single spinose cup [brunneola). 



