15 



Co 



the larva is provided with strong catting mandibles, but the inner jaws 



(fig. 3 ; middle fig.) are not adapted to masticating hard food, such as 

 particles of wood. 



The older larv;e assist in excavating the galleries, but they do not 

 eat or swallow the wood. The larvae of all ages are surprisingly alert, 

 active, and intelligent. They exhibit curiosity equally with the adults, 

 and show evident regard for the eggs and very tender young, which are 

 scattered at random through the passages, and might easily be destroyed 

 by them in their movements. If thrown into a panic the young larvae 

 scurry away with an undulatory movement of their bodies, but the 

 older larvre will frequently stop at the nearest intersecting passage 

 way to let the small fry pass, 

 and show fight to cover their 

 retreat. 



When full grown the larva 

 excavates a cell or chamber 

 into which it retires to undergo 

 its transformations. The pupa 

 cells are cut parallel with the 

 grain of the wood and generally 

 occur, as idainly shown in fig. 

 1, in groups of 8 to 12 along 

 some of the deeper passages. 



The older portions of the 

 galleries are blackened by the 

 long-continued formation of the 

 food fungus. 



The ambrosia of P. compos- 

 itus is represented in fig. 4. 

 The conidia are hemispherical, 

 and are borne in clusters upon 

 branching stems. 



The species of Platypus do 

 not attack trees in health. 

 They are attracted only by the 

 fermenting sap of dying or 

 very badly injured trees. The 

 death rattle is not more ominous of dissolution in animals than the 

 presence of these beetles in standing timber. If the timber attacked 

 by them is to be saved, even for firewood, the sooner it is cut down 

 and seasoned the better. 



The family Platypida* are essentially tropical insects; they abound 

 in (Jeutral America, lint five or si\ species, all belonging to the genus 

 Platypus, range northward from Mexico and enter the United States, 

 Three species — 7\ compositus Say. P. Jhirieornh Fab., and P. quadri- 

 dentatus Ol. — are not uncommon in the Southern States, and along the 



Fio. 3.— Details of larva of Plati/pva cotnporitut: I'pper 

 figure, Glutinous ridges upon prothoracio Begment; 

 middle figure, lower lip with inner jaws (maxilla?); 

 lower figure, mandibles and upper lip— all greatly en- 

 larged (original). 



