INSECTS. 55 



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

 of Psocidcc, which occur occasionally and are observed in many spe- 

 cies. Mr. Westwood has founded upon such specimens the genus 

 Lachesis proved by M'Lachlan to be, probably, a naicropterous condi- 

 tion of CcccUius pedicular ius. In the Kerguelen specimen the short- 

 ness 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 Psocidce with ocelli (I have stated that I be- 

 lieve the Kerguelen specimen to be icithout oceWi) two genera have legs 

 with S-jointed tarsi. But in both {llyopsocus and EUpsocus) the 

 second joint is much shorter than the third, and the antennoe only 

 ISjointed. Of the species described for those genera E. pumilis 

 from New York is not very much larger, and is similar in colors. But the 

 reticulation is very different and ocelli are present. In m}' two speci- 

 mens the antennce and tarsi are broken. 



Among the Psocidw without ocelli only Psoquilla could be taken into 

 account. The tarsi are of the same shape, the palpi also; the antennae 

 are equally multiarticulate, but Psoquilla ijossesses 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 PsylUpsocus, founded by Baron De Selys Longchamps on 

 Psocus pedicularius Rambur, approaches this species more nearly in regard 

 to the reticulation of the fore-wings, and has 3-jointed tarsi, but noth- 

 ing is stated about their length, or about the presence of ocelli, or the 

 number of joints of the antennai. The single specimen, in bad condi- 

 tion, is perhaps also exotic, that is, imported into Paris with plants or 

 merchandise. 



Therefore the specimen, not agreeing with any known species or ge- 

 nus, must belong to a new genus, which I name Rhyopsocus. The char- 

 acter of the genus would be sufficiently established; ocellis nullis; an- 

 tennis 20articulatis palpis maxillaribus articulo apicali magno, iruncato; 

 tarsis triarticulatis, articulis duobits apicalihus wqualibus ; alis quatuor. 



The question whether the species is introduced from America, is not 

 to be answered with certainty. All species hitherto known from Amer- 

 ca difler 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. 



