The Male Genital Armature of the Dermaptera. 431 



strong abbreviation of the organs of flight. Now, species in South 

 America on one hand, and in the Malay Archipelago on the other, 

 being simultaneously subject to the tendency towards brachypterism 

 which is so general in the I)ermaptera, will show the abbreviation 

 in the same way, so that two species, inhabiting widely separated 

 districts, may both show similar brachypterism by convergence, 

 and therefore fall into the genus Pyge as originally defined, without 

 being actually closely allied, and I think that the genital armature 

 will more truly show the phylogenetic relationship, and be less 

 subject to convergence, than the development or abbreviation of 

 the organs of flight. I feel therefore justified in re-arranging the 

 genera about their respective types according to the form of the 

 male reproductive organs. We at once see that the genera, as 

 thus re-arranged, fall into more natural geographical groups. 



There are two types of virga. One is very long, many times 

 as long as the metaparameres, and coiled ; this is seen in Acrania. 

 The other type is short, and may be strongly bent, with or without 

 a chitinous reflexed lobe at the base, or straight and simple. 



The metaparameres are of four types — broad, dilated, as in 

 Pijgidicrana ; lanceolate, with lanceolate tooth, as in Dicrana and 

 Acnodes ; apically knobbed, with a broad tooth, as in Kaloerania, 

 Cranopygia, and Tagalina ; or knobless, and curved into a sharp 

 hook, as in Acrania. 



I have wished to avoid creating new genera until more extensive 

 material is available, and have confined myself to erecting one for 

 Kalocrana picta and its allies, with a very distinctive form of 

 metaparameres and virga ; but probably new genera will be required 

 for Acrania horsfieldi, Kaloerania dsemeli, and Acnodes amcricana. 



In Acrania picta Guer. the manubrium is parallel-sided, 

 rounded at the tip, a little broader than long. 



Table of Genera. 



1. Metaparameres nee dentati nee rnucronati, sed 



dilatati; (genus americanum) . . .1. Pijgidicrana Serv. 



1,1. Metaparameres vel rnucronati vel dentati; 

 (genera mundi antiqui, Acnode americano 

 excepto). 



2. Metaparameres lanceolati, denti forti et 

 acuto, angusto ; genera ethiopica. 



3. Caput pronoto angustius ; segruen- 



tum penultinum ventrale 6 an- 



gustum . . . . .2. Picrania Burr. 



3, 3. Caput tarn latum quam pronotum ; 



segmentum penultimum ventrale 



$ latum. 



4. Elytra et als» perfecte explicata 3. Dicrana Burr. 

 4, 4. Corpus omnino apterum . 4. Acnodes Burr. 



2 h 2 



