1898.] ENTOMOLOGICAL NEWS. 239 



toward the base. Sides of prothorax and abdomen beneath widely 

 clothed with white squamiform hairs like those of the upper surface. 

 Third antenna! joint a little wider than in webbii ; scutellum transverse. 

 Length 21 31 mm. My series of webbii varies from 26 to 38 mm. 



The habits of the two species are apparently identical, both 

 frequenting the willows which line the banks of the Colorado 

 River and its tributaries, and among which they may be seen 

 flying in the hot sunshine of midsummer. Some of the pleas- 

 ures incident to their capture have already been alluded to by 

 Mr. Wickham ENT. NEWS, October, 1898 and are fully 

 appreciated by the writer. 



The external sexual characters of Chalcolepidius are rather 

 constant throughout the genus. LeConte does not mention 

 them, but Cand6ze says that the 's have the front tibiae and the 

 last joint of the front and middle tarsi ciliate within. In addi- 

 tion, it may be stated that the antennae are often obviously longer 

 in the males, in which sex the last ventral segment is always 

 rounded at tip, while in the female it is as constantly widely 

 truncate and furnished with a dense brush of claviform hairs. 

 This structure is remarkably like that in the 9 's of certain Cer- 

 ambycid genera Tragidion, Oxoplus and perhaps others and 

 though I have not seen it mentioned, is so obvious that it can 

 hardly have escaped notice. In one group, including our 

 smaragdinus and viridipilis the antennae are pectinate in the 

 males. 



In all the S 's of tartarus which I have examined the ciliation 

 of the tibiae and tarsi above mentioned is so feeble as to readily 

 escape observation, and the species appears to be peculiar in 

 this respect. 



Our six species are easily separable by the following table : 



Antannae of males not pectinate. 



Elytra brownish red. (Lower California). . . . rubripennis Lee. 

 Integuments black throughout. 

 Thorax and elytra with white border. 



Body without or with very few white squamules beneath; elytra very 

 freely striate. (Arizona, Southeastern California). webbii Lee. 

 Body beneath densely clothed with white squamules at sides, elytra 

 more deeply striate. (Arizona, Yuma, Plxmixi. tartarus n. sp. 

 Vestiture entirely olive green; thorax quite deeply sinute imme- 

 diately before the hind angles, which are therefore unusually 



prominent. (Arizona, Tucson) behrensii (.'and". 



Antenna- of males pectinate. 



Yestiture of body bright green, of legs deep blue. (Arizona i. 



smaragdinus 1 



Vestiture of body and members entirely olive green. -Atlantic 

 region, Texas) viridipilis Lee. 



