1922] Brolemann: Female Paraiulids 285 



projecting caudad ("heart-shaped projection").* The outHne 

 of the synoperculum, the depth of its apical notch, the size 

 of the heart-shaped projection are different in each species 

 and supply good criteria for the identification of adult females; 



Before entering into further details as to each particular 

 case, some of the general features of the species under con- 

 sideration may be mentioned. In Paeromopus the ventral 

 duplicature of the mandibular stipe is short and more or less 

 angular, while in Paraiulus it is produced into a rounded lobe, 

 reaching about half the length of the cardo. Ralph V. 

 Chamberlin has published a drawing of the gnathochilarium 

 of a male Paeromopus lysiopetalinus (Ann. Entom. Soc. Amer., 

 Ill, No. 4, 1910, PI. XLIII) which agrees almost entirely 

 with our own, except that no plates are represented between 

 the gulaf and the base of the stipes. In Californian cf and 9 , 

 P. Chamberlini, as well as in 9 P. lysiopetalinus (Fig. 1), 

 two symmetrical narrow stripes are found, considered to 

 represent the intermentum. However, a sexual dimorphism 

 might account for this discrepancy and the matter has therefore 

 to be investigated anew. The postmentum is constantly 

 missing. 



It has already been stated, 1902, that an intermentum and a 

 postmentum exist in both sexes of Paraiulus. However, a 

 detail was at that time left unmentioned, i. e., that the post- 

 mentum, which is independent in males, is fastened to the 

 gula in females, the caudal margin of the former being fused 

 with the dorsal concavity of the latter, as shown in Fig. II and 

 III. In the Blaniulidce, which are European representatives 

 of the Paraiulidi phylum, the intermentum and the postmentum 

 are both present, the latter always remaining independent, 

 but being entire {Blaniidince) or divided into two plates 

 {Isobatince). The female P. pennsylvaniciis examined combines 

 the two structures, as the postmentum is divided, as in Iso- 



*The origin of the "heart-shaped projection" will probably have to be sought 

 for in the "hood" of Paeromopus. While in the latter it has become an almost 

 independent plate through the effects of long lasting rectigradation, in Paraiulus, 

 it has not reached the same grade of achievement owing to reasons still to be 

 ascertained, but likely to be connected with Neotenia. 



t Since his paper, 1902 — Ann. Soc. Entom. France, LXXI — the author has 

 been induced to accept the terms proposed by Verhoeff for the parts of the gnatho- 

 chilarium. Consequently what was named mentum, hypostoma and ventral 

 plate I in said paper, is now the intermentum, the postmentum and the gula. 



