of Two undescribed Species of Thrips. 265 



exact accordance, and from vvlucli the cibarian organs differ simply 

 in amount of development, not in actual structure. 



The genera Idololhnps and Plthvothrlps of Haliday, chiefly dis- 

 tinguished from each other by the greater or less degree of prox- 

 imity between the single ocellus and the pair, appear to me to rest 

 on very doubtful and therefore unsatisfactory diagnostics ; and 

 although the species about to be described are clearly referrible, 

 the first to IdololJir'ips, the second to Phlcvotlirips, I find they so 

 closely resemble each other that the differences seem rather those 

 of magnitude, of sex, or, at most, of species, than of any higher 

 value ; characters indeed, which, if made the foundation of 

 genera, seem likely to induce that minute subdivision which, in 

 too many instances, is becoming not only the stumbling-block of 

 the student, but the opprobrium of our science. 



Genus Idolotiirips, Haliday, 1. c. 



Caput longissimum, teres. AntenyicB graciles, 8- articulatae, thoracis 



latitudinem triplo vel quadruplo superantes. Z«/>?'prt//»'papilli- 



formes. Ocelli tres, anticus distans, remotus ab antennarum 



basi. Prothorax intequalis, tuberculatus. ALp quatuor, an- 



ticarum radius unicus, prope basim divaricatus, fereobsoletus. 



Abdomen elongatum, excavatum. 



These characters are slightly altered and modified from those 



given in the Museum Catalogue, which are " compiled from Mr. 



Haliday's MSS." 



Sp. 1. Idolothrips Halidayi, Newman. 



Nigerrima, glaberrima ; antennis gracilibus, flavis, basi apiceque 



nigris ; capite elongato, cylindraceo, nigro-piceo ; alis fuligi- 



noso-hyalinis, eradiis, nigro-ciliatis ; tarsis Ijete flavis ; ab- 



domine valde elongato, pedetentim attenuato, segmento apicali 



cylindraceo, longissimo. 



Corp. long. '25 unc. Alarum dilat. '2 unc. 



Head three times as long as broad, cylindrical, pitchy black ; 



eyes large, lateral, oblong, seated at the anterior extremity of the 



head ; antenna; very slender, 8-jointed ; the first and second 



joints robust, slightly incrassated exteriorly, black, the apex of 



the second tinged with yellow ; the third very slender, longer 



than those next following and pale yellow ; fourth, fifth and sixth 



slender, slightly incrassated externally, and pale transparent yellow, 



tipped with black ; seventh rather shorter, subfusiform, and en- 



tirelv black; eighth extremely slender, fusiform, very acute, and 



