522 Transactions of the Society. 



and the bow of the post-frontal and length of the occipital sutures, 

 to which we must add the shape of the sternal plates. 



Zacher begins by dividing the Psalidie into two groups, one 

 with tin; virgii developed, the other in which the virga is absent or 

 aborted. This seems a very tempting arrangement, especially as 

 the virga seems to be well developed in the American genera and 

 absent from Old World forms. Unfortunately I am forced to the 

 conclusion that the abortion of the virga is not only not correlated, 

 as Zacher suggests, with brachypterism and apterism, but has no 

 apparent connexion with geographical distribution, and is not a 

 phylogenetic character. Not only is it developed in the Australian 

 Tvtanolabis and its allies, but it occurs sporadically in several 

 Indian and Ethiopian species which seem to have very close 

 affinities with neighbouring species in which no trace of virga can 

 be distinguished. It seems to me that in these cases it has not 

 even the value of a generic character, yet I feel obliged to erect 

 separate genera for those species which have a virga. The question 

 is rendered more difficult by the fact that the virga is often difficult 

 to discern ; thus in two mounts of E. penicillata there is no trace 

 of virga in one specimen, but it is quite clear in another. In old 

 and dried specimens, too, I am often in doubt whether certain 

 structures are a virga or mere chitin-plates. I question, for instance, 

 the identity of the virga in Psalis and in Mandex and Mctalabis. 

 Zacher fails to recognize it, and yet his figure shows it in Logico- 

 labis, perhaps in his " Eulabis dentata," and in Anisoldbis vcrhoeffi. 

 In my specimens of the latter it is quite distinct. 



I draw swords, too, with Zacher with regard to his statement, 

 " wenn nun Burr sagt ' Carcinophora seems to coincide with Psalis,' 

 so hat er darin ganz offenbar unrecht, da nur Psalis eine Virga 

 besitzt." He is here simply begging the question, for he relies on 

 his own determination of a " Carcinophora sp." from Brazil, in the 

 Berlin Museum, which has no virga. Now Carcinophora was 

 erected by Scudder for C. robusta Scudd., which is only a brachyp- 

 terous form of Psalis gagatina, congeneric with P. americana 

 Beauv., the type of Psalis, and, as my figures show, the genitalia 

 of the two species agree very closely, and both have a virga. 

 Carcinophora is only applicable to brachypterous specimens of 

 Psalis, and the creature from Brazil described by Zacher must 

 belong to another genus. Oddly enough, he hardly refers to the 

 genitalia : he says the preputial sacks have no chitin-plates, and 

 he implies the absence of the virga, but makes no mention of the 

 parameres. He states that the virga is absent ; in my specimens of 

 " C. robusta " it is at least as well developed as in Psalis americana, 

 but I question the identity of the structure, in both, and am in- 

 clined to regard it as a mere chitin-plate. In all other Psalids the 

 virga is a simple delicate tube, a mere non-differentiated extension 

 of the ejaculatory ducts. 



