The Genus Hylastes, Er. 125 
In the case of the adults, sketches were made from mounted specimens by 
means of a simple dissecting microscope and a camera lucida of the Abbé type 
adapted for use with low power magnification. This type of camera is not iu 
common use in Britain. It was originally designed by the Leitz firm, but, at 
my suggestion, it has been copied and is now obtainable from Watson & Sons 
of London. It has proved extremely useful for obtaining sketches for the 
comparison of general characters in species, and in the study of Hylastes 
especially, as affording fairly accurate sketches indicating the relative propor- 
tions of the thorax and elytra in the various species. 
For more detailed structure a binocular dissecting microscope and a 
Porro prism have proved most useful, as also for the preparation of slides for 
examination under the higher powers of the ordinary compound microscope. 
For general structure, magnifying powers of 8,16, 20 and 50 diameters 
have been used, and for detailed structure the 41-inch and 2-inch objectives, 
used in combination with a No. 4 eyepiece. Two pairs of fine-pointed forceps 
and a pair of dissecting-needles have proved all that was necessary for 
dissection purposes. 
In examining detailed structures, such as the mouth-parts, the meso- and 
meta-terga, and tergites of the abdomen, boiling in 10 per cent. caustic potash 
was resorted to, and the parts when clear were washed in water and alcohol 
and, after clearing in clove oil, were mounted in Canada balsam in the 
ordinary way. The same methods were used in the examination of the 
gizzard and the chitinous parts of the genitalia. 
Examination and preparation of the reproductive organs and alimentary 
canal required more care. These were dissected out in a 10 per cent. solution 
of salt and water, fixed in corrosive sublimate, stained with borax carmine, 
passed through the usual alcohols and mounted in Canada balsam. 
Generic Characters. 
According to Fowler‘ the members of the genus Hylastes show the following 
characters :—“Hyes not divided; funiculus of antennz seven-jointed, the 
first joint large and shining, the second short; club of antennz ovate; thorax 
not prolonged over the head, not bordered at the sides; anterior coxe 
contiguous; third tarsal joint dilated and bilobed.” 
Of the three species of the genus under review, I have chosen ZH. ater, 
Pk., as the type for description and comparison. It is the largest species of 
the genus, and is nearly always to be found in numbers in most districts where 
pine woods occur. 
* Coleoptera of Great Britain and Ireland, vol. v. p. 482. 
