COLEOPTERA 



541 



Among the smaller members of this subfamily are two exceedingly- 

 important pests of stored grains; these are the granary-weevil, 

 Caldndra grandria, and the rice-weevil, Caldndra oryzaz. The rice- 

 weevil is so called because it was first found in rice in India ; but it 

 infests various kinds of stored grain; and in the South it is fully as 

 important a granary-pest as is the granary-weevil. 



The two species are quite similar in appearance ; but the granary- 

 weevil is the larger, measuring from 3 mm. to 4 mm. in length; 

 while the rice-weevil measures less than 3 mm. in length, and differs 

 from the granary-weevil in having the elytra marked with four 

 reddish spots. The thorax of the rice-weevil is closely pitted with round 

 punctures; that of the granary -weevil, with sparse elongate punc- 

 tures. 



The adult female of both of these species gnaws a tiny hole in a 

 kernel of grain and then deposits an egg in it. The larva feeds on 

 the grain, becomes full-grown, and transforms within the kernel. The 

 adult continues the injury begun by the larva, eating out the inside 

 of the kernel. 



The most effective method of destroying grain-weevils is by the 

 use of carbon bisulphide. The grain is placed in a tight bin or other 

 receptacle, and the carbon bisulphide is poured into a shallow tin 

 pan placed on top of the grain, and then covered with blankets to 

 keep in the fumes. Two or three pounds of carbon bisulphide should 

 be used for each 1000 cubic feet of space. Care should be taken 

 not to go near the bin with a lighted lantern or fire of any kind until 

 after the blankets have been removed and the gas has been dissipated. 



Family PLATYPODID^ 



This is a small family, which is represented in 

 our fauna by a single genus. Platypus, of which 

 only five species have been found in America 

 north of Mexico; these are found chiefly in the 

 South and the Far West. 



Formerly this group was classed as a subfamily 

 of the ScolytidcC. It is distinguished from the 

 Scolytidag by the fact that the first segment of the 

 anterior tarsi is longer than the second, third, and 

 fourth together. The form of the body is cylindri- 

 cal (Fig. 665) ; and the head is large, wider than the 

 prothorax. 



The species of this genus attack many kinds 

 of conifers and deciduous trees. They bore deeply 

 into the heart -wood, making "pin-holes" that 

 often render liimber useless. The eggs are de- 

 posited in the galleries; and the lan^as feed on a 

 fimgus, which is cultivated by the beetles and is 

 known as ambrosia. In this respect Platypus resembles several genera 

 of the Scolytidae, which also bore in solid wood and feed on ambrosia ; 



Fig. 665. — Platypus 

 wilsoni, female. 

 (After Swaine.) 



