228 [January, 



or ambulatorial type. The posterior coxae also differ greatly in the two fami- 

 lies, those of Haliplus being dilated into a broad plate, under -which the poste- 

 rior legs can be withdrawn. We must, therefore, conclude that the differences 

 between Amphizoa and the two families just mentioned, are not of greater 

 valse than the differences between those two families themselves. 



The other relations of this insect from the form of the tarsi, would appear to 

 be slightly towards Parnus. The roughness of the surface above and below is 

 of a peculiar nature, and resembles very much what is found in certain Bupres- 

 tidas ; in fact, from the general appearance of the insect, it would at first sight 

 be supposed to have some affinity to the broad Madagascar Buprestidae forming 

 the genus Polybothris. Of its habits nothing is known. 



I would therefore divide the group now under consideration into four families, 

 thus : 



A. Mesosternum parvum ; (antennae filiformes, oculi duo, coxae intermediae 

 globosae.) 



1. Pedes ambulatorii, tenues, coxae posticae transversae,mediocres. Amph]zoid;e. 



2. Pedes subnatatorii, tenues, coxae posticae magnae laminatae. HaliplidjE. 



3. Pedes postici natatorii, compressi, coxae posticae magnae, sim- 



plices. Dytiscid-e. 



B. Mesosternum maximum; (antennae breves, perfoliatag, oculi quatuor.) 



4. Pedes posteriores natatorii, valde compressi, coxce intermediae 



triangulares planae. GYRiNiDiE. 



Having now ascertained as far as practicable the position of Amphizoa, we 

 may proceed to the specific description of the only species yet obtained. 



A. in s ol e n s, atra, opaca, subvirescens, glabra, thorace scabro, canalicu- 

 lato, antrorsum angustato, lateribus subserratis, ad medium subangulatis, 

 postice subangustato, angulis posticis acutis, elytris ovalibus, substriatis, 

 scabro-punctatis, thorace dupio latioribus. Long. '52. 



Sacramento, California, collected by Mr. J. Childs, and given me by Mr. 

 Rathvon. Color dull black, slightly tinged with greenish, without lustre. Head 

 irregularly rugous and punctulate, with two shallow impressions between the 

 antennae. Labrum covering the obtuse mandibles, slightly and broadly emar- 

 ginate in front. Thorax twice as wide as the head, flat, scabrous ; sides sub- 

 serrate, strongly narrowed from the middle to the apex, slightly narrowed and 

 subsinuate posteriorly ; base very broadly bisinuate, posterior angles acute; 

 disc channeled, with a shallow impression each side at the base, and a broad 

 transverse one before the middle. Elytra broadly oval, slightly convex, nearly 

 twice as wide as the thorax, scarcely one half longer than wide, scabrous with 

 shallow punctures, striate with nine slightly impressed grooves, which appear 

 coarsely and indistinctly punctured. Scutellum flat, broad, acute at apex. 

 Under surface of the body covered with shallow confluent punctures and 

 wrinkles. Legs scabrous with fine elevated punctures. No sexual difference 

 observed in five specimens examined. 



Stenocohts Lfc. (Atopidae.) 



Tarsi elongati tenues, unguibus simplicibus, paranychio bisetoso ; caput 

 clypeo distincto, antice membranaceo ; mandibulac apice integrae ; antennae 

 elongatae, serratae, articulo2ndo minuto ; palpi maxillares breviusculi cylindrici. 



This genus resembles in its characters Anchytarsus Giierin., but differs in 

 having a distinct transverse suture each side between the antennae ; in the 

 middle this suture is not obvious, but the front is slightly elevated, so that the 

 guture appears slightly sinuous ; the anterior part of the clypeus is membra- 

 neous ; the labrum is transverse and rounded ; the eyes are round, the proster- 

 num projects posteriorly, and the mesosternum is concave ; the tarsi are long 

 and slender, the first four joints are very slightly pubescent beneath, and 

 the first joint is a little elongated; the last joint is as long as the three pre- 

 ceding united. The claws are moderate and simple ; the intermediate appen- 

 dage is small and terminates in two bristles. 



