THE HUISACHE GIEDLER. 3 



DESCRIPTION. 



The beetle belongs to the family Cerambycidse, subfamily Lamiinse, 

 tribe Onciderini. One of the chief characteristics of the tribe is 

 that the front coxal cavities are angulated on the outer side and 

 closed behind; the antennae of the male are much longer than the 

 body, and those of the female are as long as the body. 



THE BEETLE. 



With this species the antennae of both sexes are longer than the 

 body, and there is little difference in the antennal length in each sex. 

 The beetles (PL I) are brownish gray in color, and measure in length 

 from 18 to 24 millimeters, the average length being 22 to 23 milli- 

 meters. The mesothorax is wider than in some other species of this 

 genus and measures on an average from 7 to 9 millimeters. In a 

 short time after emerging from the pupal case the beetles lose more 

 or less of their brownish-gray appearance, as the hairs covering their 

 blackish elytra or wing covers are rubbed off, causing them to ap- 

 pear darker in color. This species, like its near relatives, has about 

 one-third of its wing covers more grayish than the remaining two- 

 thirds. The posterior margin of this densely clothed grayish band 

 extends slightly behind the meson. The head and thorax are clothed 

 with brownish hairs a little more densely than the wing-covers when 

 the beetle first emerges, but it gradually loses this brownish tinge 

 for a darker one. Ordinarily there seems to be little difference in 

 size between the males and females. Wliile the writer has found 

 specimens of each sex at times smaller than those of the other, it is 

 evident that the size depends upon the nourishment afforded the 

 larva during its growth, as this in all probability has a bearing on 

 the size of the adult beetle. 



After making a large number of measurements it was found that 

 about 60 per cent of the females were from 1 to 1^ millimeters longer 

 than the males, so we may say that the body of the female is slightly 

 larger *^han that of the male, although this will not be noticed by the 

 collector without the use of a lens. On the other hand, the collector 

 may differentiate the sexes by observing the distal joint or segment 

 of the antennae ; in the males this segment is about twice as long as 

 that of the female. The length of this segment in the males runs 

 from 4 to 6J millimeters, while in the females the average will be 

 from 2 to .3 millimeters. This method of distinguishing the sexes 

 does not requii-e the use of a lens, but one should be careful to see 

 that the distal joint has not been broken off, in the male particu- 

 larly, for then tlie specimen will not be very different to the unaided 

 eye from the female. The antennae of both sexes are quite easily 

 broken, and (hii iu^' the latter part of the mating season it is difficult 

 to find a perfect specimen. 



