no.1760. THE EARWIGS OF THE U.S. NATION AL MUSEl 1/ BURR. 455 



the female. He makes no distinction whatever between the females 



of the two. and in the males the only distinction lies in the visible 

 pygidium of /.. arcuata, which it is retracted in L. chalybea; so we sec 

 that de Bormans had no clear idea of the separation of the two. 



But an examination under the microscope of the pygidium of a 

 number of specimens of both sexes from various localities shows that 

 these apparently decisive distinctions in the shape of this organ are 

 merely differences of degree. In some the points are liner than 

 others, or longer, or shorter, sometimes almost obsolete. 



When I look at one or two specimens, they seem so distinct that I 

 wonder how I could ever confuse them. When T look at a longer 

 series, I can not make up my mind where to draw the line. 



Brunner also felt the uncertainty, for in his collection a number of 

 specimens are placed with the 

 undoubted L. arcuata form which 

 are indistinguishable from some 

 labeled L. chalybea. 



Thus we are compelled to admit 

 that a very uncertain line sepa- 

 rates the typical L. arcuata form 

 from the typical chalybea form. 

 They pass insensibly from one to 

 the other, just as the various races 

 of L. riparia. I prefer to regard it as 

 one species, under the name Labia 

 annulata Fabricius, with three dis- 

 tinct forms, varieties, races, or sub- 

 species, namely, arcuata Scudder, 

 flari scuta Rehn , and cli alybea Dohrn. 



Mexico. — Cordoba, one male 

 (F. Knab); Orizaba, January 9 to 

 16, 1897 (II. Osborn). Rehn's type of L. Jlaviscuta [1903 2 , p. 305]. 



Guatt mala. Cacao, Trece Aguas, Alt a Vera Paz, two males (Schwarz 

 and Barber). Caudell's originals (1907 2 , p. 173) of L. arcuata and L. 

 chalybea. 



6. PARAGUAYENSIS Caudell. 



Paraguay. — Sapucay, two males and two females (YV. T. Foster), 

 Cat, No. 8025. Type's and syntypes of Caudell [1904, p. 181]. 



This is a good species, falling into the same group as /,. arachidis 

 Yersin.and L.silvestrii Borelli, characterized by the pyriform orclavate 

 segments of the antennae, (fig. 1.) 



7. MiEKLINI Dohrn. 



Santo Domingo. San Francisco Mountains, one female (Busck) 

 A remarkable pale thin female, apparently new. 



This single female resembles specimens in my own collection which 

 were determined by de Bormans as L. m&klini; but is somewhat 



Fig. 1.— Antenna and forceps of labia para- 



i,i \\ ENSIS. 



