ISOPODS OF NORTH AMERICA. 613 



spicuousl}^ the distal part lightly channeled; the articles of the flagel- 

 lutii suheqiuil. Eyes oval, prominent, with iiuuierous ocelli. 



The median frontal lobe is a little produced, rounded, the lateral 

 lobes drawn out, equal in length to the width of the face or to the eyes, 

 anteriorl}^ roundl}^ truncate, provided behind with a deep semilunar 

 excavation. 



The first three segments of the thorax with the posterior margin 

 straight, the posterior angles of the epimera straight, the fourth seg- 

 ment with the posterior angles of the epimera straight, those of the 

 fifth, sixth, and seventh segments more and more bent backward, but 

 not very acuminate. 



The abdomen is semicircular, about a fifth part wider than long, the 

 epimei-a of the third, fourth and fifth segments moderately large, bent 

 backward, curv^ed on the inner margin, twice as long as wide and a 

 little acuminate. The last segment is triangular, almost as wide as 

 long, deeply sinuated on the posterior margins, the apex wide, roundly 

 acuminate, with a deep and wide longitudinal excavation above. The 

 basal article of the uropoda seen from below is as wide as long, convex 

 above; the outer branch is subdepressed, lanceolate, with the inner 

 margin straight, the outer margin curved, its greatest width equal to 

 a fourth part of the length; the inner branch is slender and a third part 

 shorter than the outer branch. The color of the dorsal surface is a dark 

 grayish red with numerous pale, irregular, oblong spots intermixed 

 arranged in two wide series separated by a small interval. The abdo- 

 men is generally of one color, with the last segment bi- or tri-punctate 

 at the base. 



It varies in having a longitudinal band of grajish white and a lateral 

 series of large spots of the same color. 



Length 13 mm., width 6 mm.; length of the second antennae 6 mm." 



«The above description is adapted from the following one of Stuxberg's: 



Porcellio ovalis, latitiidine dimidiani longitudinem prope assequente (latitud. ad 

 longitud.=45 :100), convexus, siibla?vis, subnitidus. 



Antennae exteriores latitudinem corporis longitudine a'quantes; pedunculi articu- 

 lus primus secundo duplo brevior, quartus extra profundius, supra levins longitudi- 

 naliter sulcatus, quintus longissimns, praecedente tertia parte, flagello hand multo 

 lougior, rectus, parte proximali inconspicue, distali levins canaliculata; flagelli 

 articnli inter se eadem longitudine. Oculi, ocellis congregates prominentes, ovales. 



Lobus frontalis medius paullum productus, rotundatus, laterales evoluti, longi- 

 tudine altitudine faciei vel oculis ;e<juales, antice truncato-rotundati, pone excava- 

 tione semilunari profundiore pncditi. 



Trnnci segmenta tria priora margine postico recto, epiinerornm angulis posticis 

 rectis, quartum subrectis, quintum, sextum, septimum magis magisque retroflexis, 

 sed non mnltum acnminatis. 



Cauda subcircularis, latitudine quinta circiter parte majore quam longitudine, 

 epimeris seginentorum tertii, quarti, (piinti mediocribus, retroversis, margine interiore 

 curvatis, dui>io longioribus quam latioribus, panlium acnminatis. Segmentum ulti- 

 mum trigonum, prope ieque longum ac latum, marginil>ns posticis profunde sinu- 

 atum, apice lato, rotundate acuminato, supra late et profunde Inngitudinaliter exca- 



I 



