224 



PERCY SLADEN TRUST EXPEDITION 



m 



-scutellum 



Fig. 1. Diagram of elytron of Oxyomus 

 palmarum : explanation in text. 



Oxyomus Castelnau, Hist. Nat. Col., ii, 1840, p. 98. 

 5. Oxyomus palmarum, sp. nov. (PI. 12, fig. 1, and Text-fig. 1.) 



Piceus, antennis pedibusque ferruglneis, nitidus ; capite antice obsolete, postice sat 

 dense, punctulato ; prothorace dense subrugose punc- 

 tate ; elytris longitudinaliter carinatis, carina quaque 

 alter^ fortius, carina quaque intermedia parum, 

 elevata, interstitiis grosse baud profunde sculptu- 

 ratis. Long. corp. 3 mm. 



It is very difficult either to describe or to 

 represent in a figure tbe remarkable sculpture of 

 this insect. Head slightly elevated in the middle, 

 rather densely punctured in the basal portion, the 

 punctuation becoming obsolete in front. Thorax 

 with a very dense subrugose punctuation, a com- 

 pound microscope showing very fine punctures in 

 the spaces between the large ones ; the sides are 

 slightly explanate towards the anterior angles, 

 and only a faint trace of a median longitudinal 

 depression is sometimes visible. The elytral sculp- 

 ture can only be properly made out if an elytron 

 is removed and mounted separately ; it will be 



best understood by reference to Text-figure 1, which represents the elytron dia- 

 grammatically so that all parts of it are seen at once. Between the sutural and 

 outer margins [s and m), both of which are elevated, are four well-marked longi- 

 tudinal carincB {&'*) ; down the middle of each interval between these carince runs a 

 much less elevated longitudinal ridge (i''~^), dividing the interval into two interstices (i) ; 

 each interstice is curiously sculptured, bearing a longitudinal row of shallow punctures 

 connected with one another by a shallow groove. Thus the elytron bears a number of 

 longitudinal elevations, the alternate ones being developed into strongly-marked carince, 

 while the intermediate ones remain as the much less elevated ridges. Carince 1, 2, 3 and 

 4 are not continued to the apex of the elytron : near the apex the two ridges (r' and r'), 

 intervening respectively between the sutural margin and carina 1 , and between the outer 

 margin and carina 4, become themselves developed into strong apical carince {a and a') ; 

 a^ curves round the apex of the elytron so that it almost meets a, the two being separated 

 by a slight interruption at g' ; a' projects so much that it renders the true margin of the 

 elytron very hard to see at the apex. A short carination (x) is also present near the 

 apex on the ridge intervening between carince 1 and 2 [r). Elytron If — 2 mm. long, 

 wing about 3 mm. long. Mesosternum closely punctate in front, the narrow part between 

 the middle coxae keeled. Metasternum with its central portion elevated, smooth, almost 

 impunctate, rather strongly impressed, sloping on either side down to the impressed 

 median longitudinal line ; lateral parts finely subrugose. Abdominal segments smooth 

 with very few fine punctures, except at the base, where each has a transverse series of 



