ISOPODS OF NORTH AMERICA. 613 



spicuously, the distal part lightly channeled; the articles of the flagel- 

 luin subequal. Eyes oval, prominent, with numerous 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, 

 anteriorly roundly 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 

 epimera of the third, fourth and fifth segments moderately large, bent 

 backward, curved 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 grayish white and a lateral 

 series of large spots of the same color. 



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



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



Porcellio ovalis, latitudine dimidiam longitudinem prope assequente (latitud. ad 

 longitud. =45 : 100). convexus, sublaevis, subnitidus. 



Antennae exteriores latitudinern corporis longitudine sequantes; pedunculi articu- 

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

 naliter sulcatus, quintus longissimus, prsecedente tertia parte, flagello baud multo 

 longior, rectus, parte proximali inconspicue, distali levius canaliculata; flagelli 

 articuli inter se eadem longitudine. Oculi, ocellis congregatis prominentes, ovales. 



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

 tudine altitudine faciei vel oculis sequales, antice truncato-rotundati, pone excava- 

 tione semilunari profundiore prsediti. 



Trunci segmenta tria priora margine postico recto, epimerorum angulis posticis 

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

 . sed non multum acuminatis. 



Cauda subcircularis, latitudine quinta circiter parte majore quam longitudine, 

 epimeris segmentorum tertii, quarti, quinti mediocribus, retroversis, margine interiore 

 curvatis, duplo longioribus quam latioribus, paullum acuminatis. Segmentum ulti- 

 mum trigonum, prope seque longum ao latum, marginibus posticis profunde sinu- 

 atum, apice lato, rotundate acuminate, supra late et profunde longitudinaliter exca- 



