Mayi5. i9i6 Lyctus planicolUs 275 



{canaliculatus) , as described by Xambeu, is very different from the Q:gg 

 of L. planicollis, since no mention is made by Xambeu of either the 

 strand attachment or the area of longitudinal striae, which are unusual 

 characters in the egg of a beetle. 



The end with the process (the cephalic pole) leaves the ovipositor last/ 

 and this strand may possibly be attached by the ovipositor to the pore 

 contents. The larva does not occupy much more than half the length 

 of the e^gg (Pi. XXVIII, fig. 3). In hatching, the larva backs out of the 

 egg. The eggs are easily broken, and it is probably due to this fragility 

 and the fact that they are inserted far into the pores that the eggs of 

 Lyctus beetles have apparently not been previously observed with abso- 

 lute certainty of their identity. 



SEASONAL HISTORY 



Egg laying takes place principally during the middle of May. Recently 

 hatched larvse were first observed on June i, 191 5. The period of incu- 

 bation is probably, at most, 10 days. The winter is passed in the larval 

 stage. General pupation occurs about the first of April; the pupal cell 

 (Pi. XXX) is excavated near the surface of the wood, and to this cell 

 the larvae retreat after cutting a transverse burrow nearly to the surface 

 for the exit of the adults. General emergence of the adults takes place 

 during May. Under normal conditions of the natural habitat of this 

 species (in the Gulf and South Atlantic States) activity probably occurs 

 earlier in the season. 



There is apparently only one generation annually. But the combined 

 work of the many larvae of successive broods and generations burrowing 

 through the wood results in the complete destruction of the interior and 

 the conversion of the wood into fine powder — that is, "powder-posted" 

 wood (PI. XXIX, XXX, and XXXI). 



CONCLUSIONS 



Injury by "powder-post" beetles to unfinished seasoned wood products 

 can be prevented by simply adapting a system of inspection, classifica- 

 tion, and methods of disposal of stock to facts in the seasonal history of 

 the insects, as has been recommended for many years by Hopkins 

 (4, p. 6), Forest Entomologist. Such methods have been adopted by 

 several large manufacturing companies with marked success. 



In the case of finished wood products it may often be practicable to 

 treat the wood with substances to prevent attack. Creosotes are effective 

 preventives, but they stain the wood; hence, where they can not be 

 used, in the light of the discovery of the place and manner of the laying 

 of the eggs, any substance that will close the pores will prevent oviposi- 

 tion in wood not previously infested. In wood from which beetles have 



' This is according to the law of orientation of Hallez (2). 



