THE HUISACHE GIRDLER. 3 
DESCRIPTION. 
The beetle belongs to the family Cerambycidae, subfamily Lamiinae, 
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 antenna! 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. While 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 than 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 &J millimeters, while in the females the average will be 
from 2 to 3 millimeters. This method of distinguishing the sexes 
does not require 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 the specimen will not be very different to the unaided 
eye from the female. The antennae of both sexes are quite easily 
broken, and during the latter part of the mating season it is difficult 
to find a perfect specimen. 
