ORDER COLEOPTERA : BEETLES 237 



Of the Serricornia the only family that the medical 

 officer requires to know is that of the Ptinidce, or Death- 

 watches. These are small beetles, in which the head is 

 tucked under the pronotum and is often quite invisible in 

 a dorsal view. Many of the species of this family are 

 omnivorous pests of the household and warehouse. One 

 of the worst is Anobium paniceum (Fig. 103), commonly 

 known as the biscuit-" weevil," which destroys all sorts of 

 things besides ships' biscuit, including grain, dried meat, 

 and provisions generally, books, furniture, and even, it is 

 said, opium. The larva of this species is a small sausage- 

 shaped whitish grub; the adult on first emergence is light 

 brown but soon becomes darker. Other species that eat 

 everything they can get hold of, and are consequently of 



Fia. 104.— Piinus, enlarged. Fig. 105.— A'iptiis, enlarged. 



very common occurrence, belong to the genera Ptinus (Fig. 

 104) and Niptus (Fig. 105). In Niptus the elytra are fused 

 together. Another well-known species of Ptinid is the one 

 that eats tobacco and drills neat holes into cigars, often 

 choQsing the best. Cigars that have been perforated by 

 this little beetle regain their full charm if you have patience 

 to smoke on until sufficient ash is formed wherewith to make 

 a little paste and plug the hole. 



Of the Heteromera two families attract the attention 

 of the medical officer, (a) CantharidcB,ox Meloidce ; Blister- 

 beetles. The integument is comparatively soft, the head 

 is abruptly narrowed behind the eyes to form a sort of 

 neck, the elytra are rather loose, and they sometimes overlap ; 

 the legs are long and slender, and each tarsal claw has 

 either an appendage or a tooth. Some {Meloince) are wing- 



