DIPTEROUS FAMILY PANTOPUTHALMIDyl!;. 561 



on the under suiface, or display the merest vestige of such a 

 structure. 



The trutli is that characters such as those mentioned above, 

 however valuable for the distinction of species, are of less than 

 generic importance, and, were it necessary, many arguments in 

 support of this contention might be furnished from the accepted 

 taxonomy in other families of Diptera. 



Among characters of specific importance in the genus Pant- 

 ophthalmus, may be mentioned wing -markings and, although this 

 does not apply to the males of certain species wluch have the 

 thorax unicolorous or nearly so, the viarkings on the dorsum of the 

 thorax. 



Wing-markings, in spite of their general similarity (with 

 certain exceptions) throughout the family Pantophthalmidfe, will 

 be found, if close attention be paid to details, to afford useful 

 assistance not onlj in the distinction of species, but in the correct 

 association of the sexes of the same species — a matter in some 

 cases probably of far greater difficulty. Osten Sacken, in the 

 course of a valuable disquisition on structural peculiarities and 

 characters of specific importance in Pantophthalmidfe (" Acantho- 

 meridse," Biol. Centr.-Amer., Diptera, i. pp. 65-66 (1886)), does 

 not refer to wing-markings, but writes as follows with regard 

 to maridngs on the thorax: — "The arrangement of the stripes 

 and spots on the thorax, an apparent monotony notwith- 

 standing, offers excellent characters for the recognition of the 

 species, and especially for the assorting together of male and 

 female specimens of the same species." As regards the value of 

 thoracic markings for the association of the sexes of a f^iven 

 species, the statement just quoted is only partially true. It cer- 

 tn.inly hold goods in the case of I'antophthalmus tahaninus Thunb. 

 (the synonymy given on p. 562 below is based on and supported 

 by the characteristic thoracic markings exhibited by this species), 

 and P. vittatus {Acanthomera vittata) Wied. (as also in that of 

 Rhaphiorhynchus planiventris Wied.) ; but it is entirely 

 inapplicable to a species such as Faniophthahmts pictus {Acantho- 

 mera picia) Wied., in which the dorsum of the thorax is con- 

 spicuously striped in the female, but almost uniformly silvery, or 

 at any rate without corresponding stripes, in the male. While 

 the presence of sharply-defined, dark longitudinal stripes on the 

 dorsum of the thorax (scutum) is characteristic of the female sex 

 in Pantophthalmus (and also in Rhaphiorhynchus), there are in 

 addition to P. pictus Wied., at least three species, including one 

 described for the first time in the following pages, in which while 

 the female is as yet unknown, the thorax in the male is without 

 such stripes. In these species the dorsum of the male abdomen, 

 be it noted, has a silvery sheen. It is to be hoped that males and 

 females of the species in question may ere long be caught in coiiH, 

 or bred from larvse or pupae taken in the same tree-trunk, other- 

 wise the correct association of the sexes in these cases may remain 

 a matter of doubt for an indefinite period. 



