78 NORTHERN ZOOLOGY. 



b. Gyronecha. Kirb. 



Family GYRINID^. Gyrinidans. 



XXXVIII. * Genus CYCLINUS. 



Labium transverse, anteriorly circumscribed by the segment of a circle, at the apex ciliated. 

 Labium with the intermediate lobe very short, truncated ; the lateral ones large, longer than the 



tongue, externally rounded. 

 Mandibulce very short, concealed by the labrum. 

 Maxilla with the upper lobe obsolete, the lower one unguiform. 

 Palpi very short, clavate with the last joint subsecuriform, obliquely truncated. 

 Lingua subquadrangular. 

 Antennae obliquely subtruncated at the apex. 



Body depressed, obovate ; scutellum covered ; elytra with nine obliterated furrows ; arms shorter 

 than the body. 



The genus whose characters are here given, and the type of which is Gyrinus Americanus, 

 occupies an intermediate station between Dineutus Mac Leay 6 and Gyrinus. From the former it 

 differs in having a ciliated upper-lip, truncated antenna?, and arms shorter than the body ; and pro- 

 bably in other characters not noticed in Mr. Mac Leay's brief description and definition of the 

 genus. It is distinguished from Gyrinus by its broad, depressed body ; by the different shape of 

 the last joint of its palpi, and by having no apparent upper lobe to its maxilla?: 7 it has likewise no 

 visible scutellum, and the elytra have only nine obliterated furrows, whereas in most Gyrini there 

 are eleven. The tongue (or labium of most modern authors 8 ) is much shorter in Gyrinus with 

 a pair of deep impressions. The genus here laid down appears to be widely dispersed as I have 

 specimens belonging to it from India as well as from America. 



(113) 1. * Cyclinus assimilis. Similar Cyclinus. 



C. {assimilis J niger, elytris subsulcatis : sulcorum intcrstitiis pimetulatis, apice undulatis. 



Similar Cyclinus, black ; elytra slightly furrowed, with the interstices of the furrows minutely punctured ; apex of the 

 elytra undulated. 



Length of the body &h lines. 



Two specimens taken in Lat. 54°. 



fl Annulos. Javan. i, 30, 57. 



1 Mr. Curtis, in his British Entomology, (ii, t. 79,) has figured the maxillae of Gyrinus bicolor, which have evidently a 

 spinform upper-lobe, ff. 3,) but in a very good preparation of the Tropin of G. natator, in my cabinet I can discover no 

 trace of it, in either maxilla. Can it be a sexual distinction? 



8 Introd. to Ent. iii, 419, 450. 



