chap. cm. salicachje. saYix. 1481 



Baxter, several of the species are in some seasons almost entirely destroyed 

 by the Cryptorhynchus lapathi. JMr. Baxter, jun., informs us that the species 

 of willow which are least injured by this insect are, the S. pentandra, S. decf- 

 piens, and S. nigricans. After the wood in the trunk of the tree is partially 

 destroyed, it is generally found infested by the black ant (-Formica fuliginosa 

 Latr.), which is found, not only in the wood of the willow, but in that of other 

 decayed trees, even in houses, living on the decayed rafters and wooden 

 floors. In Kirby and Spence's Entomology, these insects are described as living 

 in societies, and " making their habitations in the trunks of old oak or willow 

 trees, gnawing the wood into numberless stories, more or less horizontal, the 

 ceilings and floors of which are about five or six lines asunder, black, and as 

 thin as card ; sometimes supported by vertical partitions, forming an infinity of 

 apartments, which communicate in some places by small apertures ; and at 

 others by light cylindrical pillars, furnished with a base and capital, which are 

 arrayed in colonnades, leaving a communication perfectly free throughout the 

 whole extent of the story." {Kirby and Spencers Introd., &c, i. p. 483.) 



By far the most valuable species of willow in English woods, as already 

 stated, is S. caprea ; and on this the Trochilium crabroni forme, or lunar hornet 

 sphinx, feeds, in its larva state, upon the living wood, by boring into the trunk, 

 and thus destroying the tree. An account of this insect has been communicated 

 to the Magazine of Natural History by the Rev. W. T. Bree, of which we give the 

 following abstract : — " In the Transactions of the Linncean Society, vol.iii. tab.i.,a 

 figure of the Tro- 

 chilium crabroni- 

 forme (Jig. 1290.), 

 under the name 

 of Sphinx crabro- 

 niformis, is given 

 in its three stages. 

 Lewin, the writer 

 of the article, 

 gives it as his 

 opinion that ' the 

 caterpillar does 

 not enter the 



wood till the second year of its own age;' and he states as a reason, that, 

 ' among all the numerous larvae he has found from June to November, he 

 could perceive but a slight difference in size. Possibly, therefore, they may 

 feed on the tender bark of the sallow root the first year after they are 

 hatched.' " This, Mr. Bree thinks, is very probably the case ; for he adds that 

 he has not observed in the wood any perforations of a very small size, or 

 such as have the appearance of having been made by caterpillars newly 

 hatched. As the caterpillar eats its way upwards through the solid wood, a 

 question may arise : How is the sphinx, when it bursts from the chrysalis, 

 to make its escape out of the wood without injury ? To obviate this diffi- 

 culty, instinct directs the caterpillar, before it changes to a chrysalis, to turn 

 its head downwards, so as to be opposite to the orifice, which affords a ready 

 exit for the winged insect. A portion of the plate in the Linncean Transac- 

 tions above referred to is copied in Jig. 1290. ; in which a is the male imago, 

 or perfect insect ; b, the female imago : and in Jig. 1291.; in which c is the larva, 

 or caterpillar, in its proper situation, with its head upwards, in the act of feeding 

 on the wood ; d, the pupa, with its head downwards, preparatory to its exit ; 

 and e, the web closing the orifice by which the larva had entered, and by which 

 the imago must come out. Mr. Bree sent us the but ends of three young willow 

 trees, which had been perforated by the insect, as shown by a view of their ends 

 given in Jig. 1292. One of these, on being split up, presented the appearance 

 o^ Jig. 1292. a; and, as it did not then include the case of the pupa, we con- 

 clude that the insect had escaped. The insect enters the stems, which it perfo- 

 rates near the root, and eats its way upwards for several inches, sometimes to the 



