Insects. 



7893 



upper surface are furnished with eight horizontally projecting serra- 

 tures. The ovipositor, which opens only at the extremity, is trans- 

 versely ribbed, and has some little knobs on the under side. 



This sawfly occupies a conspicuous place among injurious insects. 

 It is the only one of this family which, although not gregarious, has 

 proved singularly destructive. In our country it has made itself known 

 by its ravages, more especially at Driebergen, Zeist, Epe, Ape 1 doom, 

 Eibergen, Groesbeck, Barneveld, Brummen, Voorst, Gorssel, Vorden, 

 Laren, Lochera and Ruurlo. It is not possible to estimate with any 

 exactitude the amount of injury caused by this insect in any given 

 year, as our foresters and keepers have so little knowledge of Entomo- 

 logy, or, rather, see so little difference in the various species of vermin, 

 as they call them, that no reliance can be placed on their observations 

 in these matters. There has been some talk of a commission ad hoc; 

 but this, like so many projects of a kindred nature, has been laid 

 aside. The injury is indeed felt, but little noticed, and the means of 

 preventing such devastations are, it appears, left to chance, or are 

 expected to come by inspiration. 



There is one fact which may tend to make the attack of this insect 

 less injurious than it otherwise would be ; that is, that the larvae much 

 prefer sickly to^ healthy and well-developed trees, or, what comes to 

 the same thing, the female lays her eggs by preference on diseased 

 pine trees. Whenever they have occurred in such numbers that both 

 sickly and healthy trees have been alike attacked it has been remarked 

 that the southern and western sides of the forest were the first to be 

 eaten bare, and had thus undoubtedly harboured the greatest number 

 of larvae. 



In Germany the devastations of this insect have been known for the 

 last seventy years. 



In 1781 they appeared in such great numbers in Pomerania that an 

 average of three hundred cocoons were found on each square Rhine- 

 land rood. In the following year they spread themselves into Mark- 

 Brandenburg. There they remained in moderate numbers till 1818, 

 but in 1819 and 1820 they suddenly spread over the greater part of 

 Franconia and Saxony, causing immense injury. In 1834 their num- 

 bers again increased to an incredible extent in the neighbourhood of 

 the Elbe. This is not the place to recount the means that have been 

 taken to restrain their ravages, sometimes with and oftentimes without 

 any good result. We refer the reader who may wish to know what 

 has been done in the matter to the special works on the subject, and 

 particularly to Ratzeburg, 4 Die Forst Insekten oder Abbildung und 



