\22 TKKRKSTKTAI. IWMII.IF.S (11" HFAJ I I'T1:r \-H KTKROl'TERA 



Family LYGAEIDAE 



Subfamily Lygaeinae 



Tribe Orsillaria 



3. A^ysiiis ericac (Scbill.) 



The sixteen specimens of Xy-^'us in the collection present so much diversity that at first it 

 seemed as though several rather distinct species were represented. Before attempting to 

 elucidate the present collection it ap])cared advisable to examine rather minutely certain of the 

 described Palaearctic species. In particular, since Evans (1929) had shown thai in discrimi- 

 nating between certain Australian species, the parameres of the male provide valuai)le ciiar- 

 acters, special attention was paid to these structures. As a result of these studies it l^ecame 

 clear that all the Yale North India Expedition material was referable to A'', ericac (Schill.). 

 tliough it has seemed desira1)le to descrilje as a subspecies a rather distinct form fmm very 

 high altitudes. 



The Palaearctic species of Nysins have been studied by Horvath (1890) whose valuable 

 key provides a satisfactory basis for further work. In this key a group of species of the 

 restricted sub-genus Nysius (now to be regarded as a genus, cf. Evans, 1929) are character- 

 ised by having no well-marked pale longitudinal ruga on the scutellum and by the bucculae 

 being distinctly lowered posteriorly and not quite reaching the posterior margin of the ventral 

 surface of the head. This group includes thymi (Wolff), ericac (Schill.) and its var. 

 ohscuratus Yiorw, cymoiJcs Spin., i^raiiiiiticola (Klti.), and groenlandicus (Zell.), the latter 

 form, which Lindroth (1931) regards as a synonym of ohscuralus Horv., being excluded by 

 Horvath on geographical grounds. As pointed out below, groenlandicus, which is found 

 in the N. of Europe and Iceland as well as in. the Nearctic region, though undoubtedly a 

 subspecies of ericae, differs in several characters from obscuratus. This group, which may 

 be known as the thymi-group, appears to include most of the species described from the 

 tropical regions of the world, but with the exception of the .Vustralasian and African species 

 described by Evans very few of these species can l:»e recognised from descriptions alone. It 

 seems therefore desirable to put on record the following notes, which, though they relate 

 only to three of the most closely allied Palaearctic forms, may hel]) to stabilise our con- 

 ception of this difificult group of species and provide a point of reference for workers studying 

 tropical and sub-tropical species. 



a. A'^. tliymi (Wolff). This species is distinguished externally by its oblong-ovate 

 shape, the posterior corial margin being rounded and ampliate (Plate \'I11, fig. 7). The 

 genital segment of the male is black and the longitudinal veins of the corium are brown or 

 Ijlackish. According to Horvath the vertex is destitute of a pale immaculate basal spot, but 

 this is actually often very feebly developed. Horvath also states that the ante-apical black 

 line on the pronotum is nblii|ue, curved forward and interni[)te(l centrally. This refers to 

 a pair of marks, of essentially the same f(jrm in all the .species, presumably th« bases of 

 thoracic apodemes, which are black and surrounded by a dark suffusion. In ericac, how- 

 ever, this suffusion generally forms a straight uninterrupted transverse band so that the 

 forward curve of the apodeme bases is less easily distinguishable. 



