406 RHYNCHOPHORA. [Scolytus. 
by a rapid movement, of the abdomen against the elytra, the loudest 
sound being produced by S. intricatus. 
The Scolyti are very much infested by parasites, and but for this fact 
their ravages might be much more serious ; these parasites consist in 
great measure of Hymenoptera of the family Chalcidide; half-a-dozen 
species of these were bred by Dr. Chapman, Chetropachus quadrum 
being much the most numerous ; he found the larve of 8. rugulosus the 
most liable to attack, a fact explained by its being notable among the 
Seolytide for not taking any pains to hide the entrance to its galleries ; 
this again is explained by the fact that this species attacks fruit trees 
the bark of which is often very smooth, and affords no crevices such as 
those afforded to S. destructor by the elm. 
Miss Ormerod (‘‘ Manual of Injurious Insects,’’ p. 184) refers to 
several methods for preventing or lessening the damage done by 
S. destructor ; as above remarked, healthy trees often repel the attack of 
the beetles by pouring sap into the burrows; a Frenchman, M. Robert, 
acting upon this principle, adopted the plan of removing the whole of 
the rough outer bark from elm trees (which can be done conveniently 
by a scraping-knife shaped like a spokeshave) ; this operation caused a 
great flow of sap in the inner Jining of the bark, and the grubs were 
found to perish in almost all cases soon after; the application of coal- 
tar, whitewash, &c., might be in some cases of service, but only to a 
limited extent; the greatest preventive of all, however, is to clear 
away and burn all the old elm trunks which are left everywhere lying 
on the ground in our parks and fields and wood-yards with the bark 
still on; these in most cases are soon found to be swarming with 
Scolytus maggots, which will very soon infest and destroy numbers of 
neighbouring trees. 
The British species are usually regarded as six in number, but I 
believe that S. carpini exists in our collections, and have added it 
doubtfully in the hope that it may be confirmed as indigenous. 
I. Second ventral segment of abdomen without pro- 
jection on its posterior margin. 
i, Elytrashining with the dorsal strie very distinct 
and regular and in no way confused with the 
punctures of the interstices which are evidently 
finer. 
1. Sutural region of the elytra with a fine series 
of punctures behind scutellum ; abdomen of 
female simple, of male with a strong tubercle 
on the third segment and a transverse raised 
prominence on the fourth segment; size 
Larger: t SFist st itet oo) ce eemtetmrs her! fo, txe! 
2. Sutural region of the elytra thickly punc- 
tured behind scutellum; third and fourth 
segments of abdomen in both sexes furnished 
witha small tubercle . . . . . . . . S. DESTRUCTOR, Ol. 
(Geoffroyi, Goeze). 
S. RarzeBural, Jans. 
