1921] NATURAL SCIENCES OF PHILADELPHIA. 261 



for the first time, showing the contrasting differences between 

 conspersa and platystylata, described on page 229. 



The females of these species are separated with difficulty, as com- 

 mented upon under platystylata. In the present insect the lateral 

 margins of the female subgenital plate on each side of the meso- 

 distal portion are produced dorsad in small plates, the truncate 

 apices of these armed with a regular series of (usually 7) equal, 

 chaetiform spines. At the base of these plates, within the anal 

 chamber on the dorsal surface of the subgenital plate, are situated 

 projections of similar character, but more reduced and bearing a 

 lesser number of spines. The size and form of these appendages 

 is subject to some individual variation. In all but these two species 

 of the genus Neoblattella known to us, the female subgenital plate 

 shows no trace of such specialization. 



The males at hand have the meso-distal portion of the supra-anal 

 plate showing some individual variation. In this sex the sub- 

 genital plate is immaculate, the dark marking of the ventral sur- 

 face of the abdomen not extending that far caudad; this is true for 

 the Argentinian females also, but not for the more intensively col- 

 ored fenif^les from Igarape-Assu, Para, Brazil. 



, Measurements {iyi millimeters). 



Length of Length of Width of Length of Width of 

 cT body pronotum pronotum tegmen tegmen 



Bonito, Pernambuco, Brazil 9.6-10.7 2.6-2.8 3.6-3.7 11.3-11.4 3.3-3.4 



(2) 

 Igarape-Assu, Para, Brazil 10.8 2.7 3.3 11.6 3.2 



Contamano, Rio Ucayali, 9.7 2.8 3.3 11.4 3.1 



Peru^' 

 Colonia Florencia, Chaco, 11.8 3.1 4.1 12.3 4 



Argentina 

 Misiones, Argentina 11 3 3.8 12.8 3.8 



9 

 Igarape-Assu, Para, Brazil (5) 9.1-10.3 2.7-2,8 3.4-3.7 10.4-11 3.3-3.4 

 Sapucav, Paraguays^ 9.8 2.8 3.5 10 3.2 



Colonia Florencia, Chaco, 3.2 4.2 12.2 3.8 



Argentina 

 Villa Lutecia, Mi,,iones, 11-12.5 3-3.1 A-A 12.4-12.6 4-4 



Argentina (4) 



Distinctly greater size is shown by the Argentinian series, appar- 

 ently a geographic feature. 



8^ This specimen, in the collection of the Academy of Natural Sciences, was 

 taken October to December, 1912. 



^* This specimen, belonging to the United States National Museum, was re- 

 corded as Blattella conspersa by Caudell, the individual being mistaken for a male, 

 Jn. N. Y. Ent. Soc, XII, p. 183, (1904). 



