306 



Arrow for liis opinion, pointing out that tlieir front femora, 

 were quite conspicuously bicIentateJ^^ In reply lie wrote: 

 ''T have carefully compared your specimens with Pascoe's type 

 of Perissojjs iJiacus, and am satisfied that they belong to that 

 species. Pascoe's collection contains five specimens, varyinp- a 

 good deal in pattern, and the one he has marked type' (from 

 Gilolo) has the prothorax almost entirely white, but I think 

 there is no doubt all are the same." Although the species 

 emhlematicus must now be regarded as synonymous with 

 iliacus, the generic name Crito?ner2is must be retained, as the 

 conspicuously bidentate femora are strongly at variance with: 

 all the (now numerous) known species of Perisso'ps. 



Mechistocerus. 

 Berosiris. 



Dr. Gestro sent me three specimens as co-types of B. 

 calidris, but as they 'vvere from Yule Island, and that locality 

 was not mentioned under the original description I thought 

 it desirable to have them compared with the type, and sent 

 them to Mr. Arrow with a note as follows : 'I w^ould specially 

 draw your attention to the walls of the pectoral canal, almost 

 attached to the hind margin of the front coxae you will notice 

 ridges margining the canal (a feature that denotes the species 

 is a Mechistocerus). These ridges are, however, easily over- 

 looked, if the specimen is pinned in the ordinary way. If 

 B. calidris (type) has these processes, possibly others of that 

 genus have, in which case possibly the name should be treated 

 as synonymous with Mechistocerus. The genus Berosiris was- 

 originally described in the Journal of the Linnean Society, (s) 

 and five species were then named. As picticollis was 

 figured *^^) and the first named, apparently it should be regarded 

 as the type; and I w^ould therefore be glad to know if its 

 pectoral canal is as in the specimens sent, especially as to the 

 processes just behind the front coxae." 



In reply Mr. Arrow wrote: ''I have examined the type of 

 Berosiris calidris, and although your specimens cannot be 

 regarded as co-types, I think they are probably the same. 

 Pascoe had specimens from Yule Island, but left them 

 unnamed and separated widely from B. calidris. The form of 

 the pectoral canal is exactly the same in all species of Berosiris 

 (including B. picticollis J as in your specimens, and Mr. Mar- 

 shall tells me that Berosiris and Meckisfocerus have long been.' 



(7) The second tooth is midway between the first and the base of 

 the femur; in several species of the genus there is a small supple- - 

 mentary tooth in the femoral emargination. 



(8),Zool., xii., 1873, p. 43. 



(9) PL i.. fig. 9. 



