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XVII. Descriptions of the British Species of the Genus 

 Gyrophsena, Group Staphylini, Family Aleocharidse. 

 By G. R. Waterhouse, Esq., F.Z.S., &c. 



[Read 2nd December, 1861.] 



Having taken considerable pains to ascertain the peculiarities of 

 the males of the species of Gyrophcena, I am anxious to say a 

 word or two, before I begin my descriptions, with the view of 

 making this matter more clear, and also of shortening the de- 

 scriptions. The peculiarities which I refer to present themselves 

 in the 6th and 7th segments of the abdomen ; and, with regard to 

 the 7th segment, are often difficult to ascertain, as in the dead in- 

 sect that segment is retracted beneath the 6th, unless care is taken 

 to fix it in its proper position by gum immediately after the insect 

 is killed. From this circumstance the structure of the 7th seg- 

 ment (which is usually very characteristic of the species) has in 

 several instances not been noticed, and in some cases not correctly 

 described. For instance, G. vana is said to have the segment in 

 question tridentate at the apex, whereas the normal condition in 

 the species of the genus is a quadridentate termination to the 7th 

 segment, and G. nana does not form one of the exceptions in this 

 respect. Among the species which have come under my notice, 

 the most perfectly developed condition of the structure alluded to 

 is seen in the male of G. gentilis. Here the 7th abdominal seg- 

 ment terminates in four elongated slender processes, of which the 

 inner pair are approximated, and rather shorter than the outer 

 pair : in other species we find the middle pair gradually becoming 

 smaller until they are quite obliterated, as in G. fasciata. One 

 species presents a remarkable modification in the 7th segment ; it 

 is the G. Icevipennis, and is noticed in the description of that spe- 

 cies. With regard to the 6th abdominal segment of the male, the 

 normal condition appears to consist in its presenting a transverse 

 row of six, nearly equidistant, short, longitudinal ridges, as seen 

 in G. fasciata; in other species we find these little ridges de- 

 crease in number by the obliteration of the outer pairs, until 

 but two are left, as in G. Icevipennis ; we find, however, a re- 

 markable exception in the G. affinis, where there is but one minute 

 rising in the form a single, and, of course, central tubercle. This 

 tubercle is perhaps formed by the union of the two central ridges 

 observed in the other species, since in G. pvlchella it is repre- 



VOL. I. THIRD SERIES, PART III. AUGUST, 1862. E 



