Die Insekten und Arachnoidee» der Kerguelen. 



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between the two horny ones are two smaller elongated, pointed, horner stems, much shorter 

 than the others. 



The color is pale brownish-yellow, darker on head and mandibles; antennae grayish; 

 wings hyaline, colorless, the long hairs of the fore-wings dark. 



Length of the body a little less than 2 mm; expanse of fore wing i'/ ä mm. Locality 

 Kerguelen Island, October 1874 ')• 



The specimen belongs, doubtless, to the so-called micropterous forms of Psocidae, which 

 occur occasionally and are observed in many species. Mr. Westwood has founded upon such 

 specimens the genus Lacl/csis proved by M'Lachlan to be, probably, a micropterous condition 

 of Caccilius pedicularius. In the Kerguelen specimen the shortness of the wings (the fore wings 

 are shorter than the body), and the reticulation not identical in both wings, show an aborted 

 condition. The systematic place is rather doubtful. 



Within the section of Psocidae with ocelli (I have stated that I believe the Kerguelen 

 specimen to be without ocelli) two genera have legs with 3-jointed tarsi. But in both (Myo- 

 psocus and E/ipsocus) the second Joint is much shorter than the third, and the antennae only 

 1 3-jointed. Of the species described for those genera E. pui/ülis from New York is not very 

 much larger, and is similar in colors. But the reticulation is very different and ocelli are 

 present. In my two specimens the antennae and tarsi are brocken. 



Among the Psocidae without ocelli only Psoquilla could be -taken into account. The 

 tarsi of the same shape, the palpi also ; the antennae are equally multiarticulate, but Psoquilla 

 possesses no hind wings, and the reticulation is scarcely related. I should add that Psoquilla 

 is known only by three specimens of uncertain locality, and not in good condition. 



The genus Psyllipsoais, founded by Baron de Selys Longchamps on Psocus pedicularius 

 Rambur, approches this species more nearly in regard to the reticulation of the fore-wings, and 

 has 3-jointed tarsi, but nothing is stated about their length, or about the presence of ocelli, or 

 the number of joints of the antennae. The single specimen, in bad condition, is perhaps also 

 exotic, that is, imported into Paris with plants or merchandise. 



Therefore the specimen, not agreeing with any known species or genus, must belong 

 to a new genus, which I name Rhyopsocus. The character of the genus would be sufficiently 

 established ; ocellis nullis; antennis 26-articulatis; palpis maxillaribus articulo 

 apicali magno, truncato; tarsi s triarticulatis, articulis duobus apicalibus 

 aequalibus; a 1 i s q u a t u o r. 



The question whether the species is introduced from America is not to be answered with 

 certainty. All species hitherto known from America differ from one another. The only species 

 I have not seen is P. pusillus Harris, but the description differs. Now it is certain, that not 

 more than ten per cent of the species living in North America are known, probably even less. 



The introduction of the Psocidae into foreign countries is very easy. Two species, living 

 in Ceylon upon the coffee-tree, have been collected near Rio de Janeiro by Mr. B. P. Mann, 



1) The only specimen noticed during the stay of the Transit Party at Kerguelen was captured October 17, within doors, and 

 was mounted in baisam upon a microscopic slide. Shortly before its capture some instrument-boxes, brought from Washington and con- 

 taining a quantity of packing-straw, had been unpacked in the some room ; a circumstance rendering the habitat of the insect very doubt- 

 ful at the time. J. H. KlDDER. 



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