450 RHYNCHOPHORA. [Platypodinw . 



sides of the thorax and the round subconvex eyes ; the head is large, not 

 covered by the thorax, and the labrurn is small but distinct; the 

 antennae are very short and have a large scape and a large compressed 

 solid club, which is pubescent except for a small space at base ; the 

 thorax is rather long and the prosternuin is moderately long in front of 

 the coxae which are large, conical-cylindrical and oblique ; the meta- 

 sternum is very long ; the ventral segments are five in number and un- 

 equal ; the elytra are elongate and cylindrical and sloped or subexcavate 

 at apex ; the legs are short with the femora dilated, the tarsi long and 

 slender and the claws simple. 



The larvae of the genus Platypus differ somewhat from those of the other 

 Scolytidae, as may be seen by comparing Westwood's figures (Classifica- 

 tion I. p. 350, fig. 42, 4, 14, 22) ; the head is large and the body short 

 and straight and not curved towards the extremity, Avhere it is somewhat 

 obliquely truncate, and the sides of the body are furnished with rows 

 of distinct tubercles ; the pupa is elongate with the intermediate 

 coxae very large, considerably larger than in the ordinary Scolytid 

 pupae. 



The life history of Platypus cijlindras has been very fully described 

 by Dr. Algernon Chapman (Ent. Monthly Magazine, viii., pp. 103 

 132); the following account is abridged from his observations, which 

 are exceedingly valuable ; the beetle burrows into solid wood, and, in 

 consequence, is difficult to observe ; these burrows, in which both per- 

 fect insects and larvae are found, have always an extremity open on the 

 side of the stump ; they are of uniform diameter throughout, viz., that 

 of the full-grown larva and perfect beetle, presenting no narrow 

 burrows of young larvae, as observation of most of the other Xylophaga 

 would have led us to expect ; and the inhabitants are not confined each 

 to its own branch of the burrow, but the larvae, to the number of from 

 frixty to a hundred, together with the perfect beetles, their parents, run 

 actively backwards and forwards in the burrows, and from one branch to 

 another, getting out of each other's way, backing into a branch to let 

 another pass, just as a train is shunted into a siding. The usual 

 habitat of Platypus is in oak stumps, but it also occurs in beech ; it only 

 attacks stumps that have entered on their first period of decay, but are to 

 all appearance sound ; the chief essential appears to be the presence in 

 the wood of a certain fungus, which probably lives in the fermenting 

 and decomposing sap, and which half fills the galleries in which, the eggs 

 are laid, and serves as food for the young larvae. 



During July and August the beetle emerges from the pupal state, the 

 greater number during the last week in July, and at this period they 

 commence their burrows ; occasionally an odd burrow is found, but 

 usually the burrows are in colonies, and as many as fifty entrances may 

 be found on the side of a stump scattered over a surface twelve to fifteen 

 inches wide and four or five high ; the burrow from its mouth on the 

 surface of the stump is a perfectly clean cut cylinder. 



